Just give him potty opportunities. he should pick it up in a few months.
At 15 months, i started potty learning with my older kids. We would just have naked time in the morning. I would also take them after nap. It takes 12-15 hits (success) for them to understand how to control the muscles. Once they are doing this, I then put them on a schedule. By 18 months, they started takingthemselves..and by 21 months they night and poop trained. With that said, both had accidents up until 4, and my oldest even had an accident recently and she's 5.5! Accidents happen. In fact, the other day I almost didn't get to the toilet in time! The most important thing is to just accept them as part of life, and move forward. Don't get mad or show any negative emotion.
I have a just 9 month old baby that I may start doing EC with when I have the energy. She wakes dry from her naps, and she lets me know when her diaper is dirty, and I'd like to not train her to sit in a dirty diaper. It's never too early to teach about wet/dry, etc. The most important thing is to not put too much energy into it, or you will create an area of power struggles.
Once he takes himself 90% of the time, put him in training pants. Do not use pull-ups! Gerber makes great training pants, use those so they feel the mess. Expect accidents...2 is a very distracting age, so it's important that (1) you have a schedule in place, and (2) you don't push it or make a big deal when they have an accident. Also, they have regressions before leaps forward in ability, so if all of a sudden he has non-stop accidents, just say "oops, we didn't make it in time, next time we will." Be unemotional about it, and indifferent, and just hang in there. Regressions last 2-7 days, and then usually they show advancements of some sort.
Good for you for noticing the signs! Many people think them taking off their diaper is a game. It isn't, it's them saying," hey! I don't want to have this thing on me! it's dirty!"