How do I hook up my pre-wired house for cable?

You should check in your basement or crawl space. That is usually where the cable line should be run to be distributed to the rest of the house. You should see some kind of splitter that you can plug the incoming cable into. If it were me I would also run the cable through some PVC pipe and bury it so you don't have to worry about it getting messed up from laying on the ground.