A lot of pop music producers will start with a basic four-chord pattern, I–V–vi–IV. For example, if you are in the key of C Major, you would play a C Major chord (CEG), a G Major chord (GBD), a A minor chord (ACE), and an F Major chord (FAC). That is a popular "template" so to speak that can lay down the basic line for you to put other instruments over.
If you really want to get involved, a little bit of music theory never hurt anybody. You don't need to know much to get a basic understanding of the way things work.
I hope this helps :)