Hi there, here is some information that could help with your project.
Here's a video tutorial for painting particle board. Good luck! https://www.youtube.com/watch?v=5up7g7Ks4WA
These tips might be useful
Paint will adhere better to particle board that has been primed. You can use either a spray or regular primer on the board. Apply primer, and then wait for it to dry completely. Once it's dry, sand the particle board again lightly with 220-grit sandpaper.
Prime first then paint. You may want to sand before priming depending on what you've used/made with it. Everyday touching/using I'd sand first, outside/garage/shed etc. don't waste your energy. Depending on if you have sanded or not would also determine if you need longer/thicker napped roller. you could use KILZ or Zinsser primer