What is the process for extending a 60-day tourist visa in Samui, Thailand?

When you arrive you'll want to head to the little building on the right to get copies of your passport which they will help you with, but they do charge a small fee (like 15baht). Once you have your copies and photos you can head up to the main building to fill out the form. There's usually someone there to help you, as it's not always straightforward if you haven't done it before, but just ensure someone checks it over for you before you hand it over. Inside you'll wanna get in line to get a que number where you'll wait for that to be called to go up to the desk. It's all pretty straightforward but can be flustering if you've never done it and the office is a gong show. I went yesterday at around 130 and it was nice and quiet.

Take your passport to Samui immigration. Tell them what extension you want. You can get any forms printed or passport photos taken in booths, outside