that's changing for months... It was a case in the past. You just pay, get the student visa and that's it... Nowadays immigration coming in to the school, checking students, etc. And this is fact I'm studying thai myself and immigration just visited my class on Friday. I didn't say no chance to find a shady school where you can do this but much more harder than before.
You need?? Not really you even can convert the 30 days entry stamp to ED visa ;) I'm on ED myself and many of my classmates converted their 30 days entry stamp... So that's not real requirements...
First day. 5 hours video watching. Second day colour blindness test and spatial vision test, theory test. 50 question at least 45 have to be right..if you pass the theory test you go to do the 5 min practical test. If that's pass too go pay 105baht for the DL. Take a photo 10-15 min.and your DL in your hand. But don't forget you need residency certificate, medical certificate, and photo copy about our passport and visa.