Paint / construction work flow

Evening,

Looking for some advice?

Picking up model making again, starting with a fiat 500 tamyia kit which was a gift for Christmas along with an airbrush and a 911 kit.

What I'd like to know is paint, build process? Do you paint everything first and sort into colours or build and paint as you go? On smaller models, it means changing paint quite a bit and I feel I'm missing something.

Apologies for the silly question if it seems it.

Many Thanks