ty!

yes

I couldn't find any mdf paint, I guess I can use any wood paint?

Spray cans are cheapest with no cleanup.

so primer, sandpaper (220-ish) and whatever color I can cheaply find.

>>28419 say what, formaldehyde? Is that going to make me high? :D

Use an acrylic primer undercoat, and then paint with whatever top coat you like :)
Always a good idea to paint or seal mdf as it's full of formaldehyde and can 'off gas' in to your home :/

You want it to soak in too much. Oil base sanding sealer is the easiest coating to apply. It dries quickly and with two or three coats the same low sheen gloss will be attained without using any varnish as a finish coat. If you don't like the finished look, you can sand the last coat of sanding sealer and paint a color over it. It's recommended to sand between coats no matter what you paint it with.

It's medium-density fibreboard. I'm a bit worried it will soak in too much.

If it's raw wood, it'll dirty extremely easily. Very hard to clean dirty wood. If nothing else, sanding sealer (clear).

Primum Inflexio, inners