@Abbie *******
The choices you have is between schools, so that's where you got to start.
Ask in here or do a google search for reviews of schools in your area.
When you have decided on a school you give them a call and ask about the process, or go to visit them.
When you have signed up for classes, they will take a copy of your passport, take some passport photos and prepare the needed documents for you.
When the said documents are done, you will have to sign them.
For this part, there is really nothing an agent can do for you. I doubt many / any of them can tell you anything about the level of education in the different schools, and apart from an endless amount of signatures, there is little to no paperwork, you will have to fill out by yourself.
Very few schools can convert from a tourist visa/visa exempt to an ED visa inside the country. So you will most likely have to travel to a nearby embassy such as in Penang, Kuala Lumpur, or Singapore to get the visa attached.
By doing it this way, there is NOTHING you can do wrong. Besides showing up, there is no work in it for you, and it is really a quite simple process.
It is not my business or concern if you want to study or not, and I couldn't care less how you obtain your visa. 🙂
11 years ago when a friend 😉 moved here, he got royally screwed over by the agent that helped him obtain his ED. He didn't find out until after his 2nd year, and he ended up in A LOT of trouble. Only VERY deep pockets and a lot of luck/contacts got him out, and I do not wish for others to end up in the same situation as him.
I am really only trying to help you, and the best way I can do that is to make you forget about having an agent to "help you out".
Best of luck 🙂
Ps. There are plenty of Phuket forums on FB. Perhaps joining one of them and asking for school reviews, would be where to start 🙂