You categorically cannot conclude creation, evolution by creation, evolution or otherwise without knowing what event enabled RNA to become DNA. - Hadriel
This thread is not about the origin of life. It is about the homochirality of some organic molecules. Some creationists - for reasons best known to themselves - see this as evidence of a creator.
Kenso Soai demonstrated that in fact there is nothing unlikely about homochirality at all.
Having said that your question about the transition from RNA to DNA in the early stages of life on earth is a good one.
You should investigate the work being done by biochemist Bill Martin of the University of Dusseldorf, Mike Russell of the Jet Propulsion Lab in Passendina, and Eugene Koonin of the NIH in the USA.
There are just two tiny chemical differences between RNA and DNA. Both of them would easily have occurred spontaneously in the alkaline vents that were the nursery of life. I will explain more if you are interested.