[Closed] Growing (and pruning) chilis

Ciao bellas,
My chilis are looking good - I have a couple of established (a year old) and a bunch of seedling plants in a window tray. The established plants are fruiting for the second time, with the chilis now going red.
First question is - when are the peppers ready to pick? Is it a colour thing? Or a feel/ colour combination?
Second question is to do with pruning; after they've finished fruiting I intend to cut back the 2 main plants to allow them to grow back (and the seedlings some space to grow into). What's the best way to prune (as somebody who's never pruned anything...)?
Cheers