TBH I don't really want to give you an explicit command as rsync is an incredibly powerful tool and can be used in a multitude of ways. And TBH I'm not that familiar with it OTTOMH and I don't want to lead you astray.

Whenever I use it, I consult the docs. Here's a pretty good man page online: https://linux.die.net/man/1/rsync

Although if you are particularly newbish, then perhaps a better starting point is a tutorial like this: https://www.digitalocean.com/community/tutorials/how-to-use-rsync-to-syn...

Common usage examples may also be of value to you:
http://www.tecmint.com/rsync-local-remote-file-synchronization-commands/
http://www.thegeekstuff.com/2010/09/rsync-command-examples

Another page that I found in my googling that might be of interest is here: http://www.evbackup.com/support-commonly-used-rsync-arguments/