Jeez Louise,
What is so difficult to understand?
Here is what happened:
Jesus had some bit of bread and the little cup of olive oil, he dipped the bread and gave it to Judas or perhaps just offered the cup over to Judas and Judas took the bread out of the cup and ate. No one thought anything about it at the time, even though Jesus evidently said something about the one who is "sharing his bowl" or (in other words) the one he is giving the morsel to will be the betrayer or is the betrayer.
At least a decade later or even more in the case of John, when it seems necessary that it is important to write down an account of Jesus life and sayings, Matthew and John both relate their take on what happened. Keep in mind that this is many many years since.
John remembers and writes things pretty straightforward but with special emphasis on the fact that they realize NOW that Jesus identified Judas before he betrayed him (thus highlighting Jesus divine powers of prescience which is in line with John's whole view of Jesus of highlighting his divinity). John's recollection is that Jesus said in answer to Peter's question of "tell us who the betrayer is" that Jesus said "it is the one to whom I give the morsel to eat and that he gave it to Judas."
Mathew, who is more concerned about preserving the Jewish tradition and emphasizes the Jewishness of Jesus records the situation a little differently. As Matthew recalls it, Jesus said one of them was about to betray him, they each ask essentially "It isn't me is it?" (No doubt they are very puzzled and as the scripture said "grieved" to think that they might be the one to betray Jesus, so I wanted to know). Matthew recalls that Jesus said something along the lines of "its the one that dips the morsel in this bowl" . Matthew leaves the act of Jesus actually passing the morsel or the bowl with the morsel over to Judas implied but records Judas's question "It isn't me Lord" immediately following Jesus's words.
Remember these guys were writings many many years after the fact and each had their own slightly different personal philosophy about what was important about Jesus. The two accounts are not a contradiction.
We don't have to worry about whether one account is more accurate than the other, whether they are both correct or maybe whether they both got it wrong.
The point of the scriptures is so very simple that it is too often not ony misunderstood but misapplied by persons.
I will make it extremely simple for you:
THE BIBLE IS NOT ITSELF THE REVELATION ABOUT GOD TO MANKIND.
THE BIBLE IS A RECORD OF THE REVELATION ABOUT GOD TO MANKIND.
One must therefore be very cautious about being overly concerned about specific wording, scriptures or passages (nor do I need to add that it is pure folly to base entire doctrines on the turning of a phrase, word or tittle).
Try to see the big picture and you won't go wrong.
-Eduardo