Broke my screen, what is the best way to still utilize the computer?

I still use it everyday for music and such, have no issue getting in, is there a way to make the broken screen disabled? And to where it uses whatever screen I have connected as the main screen?

Sorry if this is a really dumb question, I’ve been thinking of getting a keyboard and mouse to hook up since when I close it I’m assuming it makes whatever screen it’s on the main? Thanks for any help I need to be able to use the laptop without any issues for some upcoming work.