Dearest WuzDub... may you have peace!
I am not an attorney, so, unfortunately I cannot give you "legal" advice and must state to you that the following is NOT legal advice. If you need LEGAL ADVICE (as your title indicates) you should consult an attorney. However, how to get someone out of/off your property is readily available in a plethora of Landlord/Tenant-related self-help books... and on the Internet... so I am going to tell you below what such resources say you can do. What I tell you will be accurate, although NOT legal advice, however, based on my background and certifications, which are:
I have over 22-years as a housing administrator. I am a Certified Mediator, primarily in landlord/tenant issues, and more specifically Unlawful Detainer Court (as well as Small Claims court), and I am a Certified Manager of Housing (CMH), Certified Occupancy Specialist (COS), and Certified Tax Credit Specialist (TCS). I am also the Fair Housing Director for a regional agency... and I have a JD (but since I am not giving you legal advice (i.e., I am telling you what you CAN do, vs. what you SHOULD do), we'll leave the latter out).
Here is what any decent Landlord Rights book, website (just Google "How to Evict" and your state), or Superior/Small Claims/Unlawful Detainer court website will tell you:
1. Depending on your state, you MUST serve these folks with a Notice of Termination (usually 30-Day, unless you're in California and they have lived there more than 1 year, in which case, you must serve them with a 60-Day Notice). You can get a copy of a blank notice online (just type in "30- (or 60-) Day Notice" and your state). Make sure you count the days properly (weekends and holidays ARE included... but don't take for granted that the "30th" of month B is exactly 30 days from the 30th of Month A. COUNT it out. Trust me on this.
2. You MUST serve such Notice on each ADULT (anyone age 18 or over) SEPARATELY, so you'll need a notice for each one. (Note, someone might tell you that you can name them all in one notice - that's not really accurate. Since EACH person must BE served, if you only make out one notice and serve it on one person, the others can claim they were never served. To CYA, give them EACH their own notice).
3. You can serve the Notice yourself; however, it would be WISER to have someone NOT related to the matter do it (in case parties try to deny that they were properly served). That person MUST be at least 18 years old.
4. Regardless of whoever serves it, a Proof of Service form (which you can get online) MUST be completed... for EACH notice served.
5. To PROPERLY serve the Notice(s), you MUST:
a. Give it the person PERSONALLY... OR
b. Give it to someone in the household who is AT LEAST 18 years old... OR
c. Place it in/through the door (or, in some jurisdications, post it on the door) AND mail it (certified is best).
Note, you should read the Proof form FIRST... so that you know your options... and then once the notice(s) have been served, indicate on the form HOW it was done. Do NOT complete the Proof of Service until AFTER the notice(s) have been served, because you may have to testify in court as to HOW they were served... and if you serve them AFTER you complete them... it may not be what you indicated (i.e., you may check that you gave it to the person, but they actually weren't home and you posted and mailed it. The form is to say what you DID... not what you are going to do. And, yes, you will need a SEPARATE proof for EACH notice served.
6. If they are not out by the expiration date of the Notice, then you can file what's called an "Unlawful Detainer" action with the court (either UD Court or Small Claims) the very next day.
a. The EASIEST (because you do nothing but pay)... and most expensive... way to do this is to use an attorney.
b. The SECOND easist... but less expensive (because you do some of the work)... way is to use an online Eviction/Unlawful Detainer Service... or Unlawful Detainer Assistance (UDA), if your state has them. You can check the Yellow Pages for the latter. Note, some states require that UDA's be registered with the court and that's a good thing because you want someone to be accountable if mistakes are made (which could cost you your case). These are just like what the Self-Help Center will do for you (and what I am trying to do here), but charge a fee (which, depending on the situation, can run from nominal to "I-should-just-go-on-and-hire-an-attorney").
c. The THIRD easiest... but even less expensive (because there is no cost, but you do most of the work) way is to get assistance from your local Superior Court Self-Help Center. They have attorneys there who only job is to assist people with completing court forms. Like me, they can't advise you as to what you SHOULD do... but they help you do what YOU decide you should do (i.e. complete the forms, file with the proper court, etc.).
d. The least easiest... and least expensive (no cost, and you do ALL of the work) is to get the forms online (Google) or from the UD Self Help section of your local superior court website and fill them out yourself. Because of the change for errors that might cost you your case, I would stay away from this one; however, I am not "advising" YOU to do so. If you believe you can handle/do it, then by all means - you're the "boss."
7. Once the UD action is filed, the defendants/respondents will have anywhere from 5 to 30 days (depending on your state) to file a response stating THEIR side of the story. I am not sure what "story" they will have, however, as you're merely saying, "Hey, look, I want my house back... to live in... so I want/need you to get out." Which you can say and have absolutely NO other reason. A landlord (which is what you ARE, even if you didn't intend to be) can terminate a tenant (which is what they are, even if there's no written lease) residency with NO grounds IF they wish to occupy the premises themselves.
So, say:
8. They DON'T file a response within the 5-30 day timeframe (which is what usually happens). The court will consider this a "Default" and give you a Default Judgement. You must then take that document to the Sheriff so that the SHERIFF can EVICT them (NO ONE evicts except the Sheriff. An "eviction" is what occurs when the Sheriff literally comes out, tells them to get their stuff and get out, after which you change the locks - yes, you go with the Sheriff - and then the Sheriff posts a notice on the door telling them they can't go back in and if they do, they will be arrested. THAT... is an "eviction." They are "evicted" from the premises. Which is why they the process is called an "Unlawful Detainer" - they are "unlawfully detaining" the premises)... and the whole thing may actually go away/be resolved before the defendants are actually "evicted."
9. They DO file a Response (though, I don't know what their response would be; even if they say you "promised" they could live there, YOU now want to live there and so can "terminate" their leasehold. Some people file a Response, however, simply to buy some time, because):
a. In that case, the Court will set a hearing date. These dates are anywhere from 5 to 14 days out, depending on your state and the court calendar.
b. Both sides appear at the hearing* and present their arguments (cases), after which...
c. The judge issues a decision based on the cases presented by the parties. So say:
(i) Judge says they can stay (which is HIGHLY unlikely, but if so would be for a limited time)... then you have to wait until the period the judge gives them ends and if they don't move out by then, you have to file another UD action.
(ii) Judge says get out... then you receive a regular Judgment (not a "Default" Judgment) which, again, you must take to Sheriff so that he can evict them.
b. If a party does NOT appear, then:
(i) If YOU don't appear, your case will be dismissed;
(ii) If THEY don't appear, it will be as if they didn't file a Response and the judge will issue a Default Judgment will be entered which, again, you have to take to the Sheriff for eviction.
Of course, there's more if they leave, but leave their... ummmmm... "stuff." Which is highly likely, given what you say they brought with. But we can cross that "bridge" when we come to it, if you need to. In the meantime, that's it, in a nutshell.
I hope it helps and again I bid you peace!
Your servant and a slave of Christ,
SA