How long does it take for just a normal one colour paint job with rattle cans? I heard it was somthing like 2 months is that true?
Depends on the paint really, 1 or 2 months is a good time to leave it.
so is there a differents from the paint drying and setting?
The paint may be touch dry but not fully cured for a while.
So can you paint it before the paint has fully cured?
You mean add more coats? Yes you can.
Can you play it before it cures?
You could but it's not a good idea as the paint will be softer and damage easier until it's cured.
fine to play as long as you're gentle, no gigging.