How to divy things up using threads

I’m sorry if this is a re-ask, but when trying to separate actions into threads, what should you consider, the only thing i can think of is that every variable affected, assuming this is a new thread not the main one running the game loop, must be declared volitile. Is that all that need to be done? and should the game update loop and render loop be on separate threads? ty for all help.

This thread should answer your question. (I know it is a little hard to find ;D )