Trouble connecting multiple ethernet cables

I recently upgrade my internet speed to 1Gbps and I had to change my router (Provided by Comcast) as it wasn't compatible with the new speed. I bought a modem recommended by a friend (Netgear CM1200), but it only allows me to connect my PC using ethernet port. After searching on Internet I discovered that modems can provide a single IP that Comcast gives to you and that I need a router to allow me to use more ethernet ports. Now, with my old Comcast modem I had connected multiple devices using ethernet ports. So my question is whether I can use a Modem/Router like the Netgear C7800 to connect multiple devices via ethernet cable or I have to pay to Comcast for one that I could use?

P.D: I dont want to have a modem and a router separatly, I just want a single divice that alows me to connect my PC, XBox, Playstation, etc via cable.