If you want to use your own router, then I recommend you contact your ISP, and you tell them that you want to use your own router. If your ISP won't allow you to use your router, then I suggest you get a different internet package. You might have to look, for a new ISP.
You would have to tell your ISP that you want to use one of their modems, and you want to use your own router. The sad thing is if you don't know anything about routers, then I think you might become frustrated. When I had my own router, my ISP didn't help me to set it up, so you're going to have to figure it out by yourself, or you're going to have to hire someone to set it up, for you.
I have used a modem/router combo, and I like it.