First of all you need to have a functional home wire installation. A copper pair wire running trough your wall from the socket to the connection point in your building/neighborhood. Then you need to contact the optimal ISP and sign a contract, they will supply the router. After the router is installed and your internet service is working, you need a Ethernet cable that is used to connect your PC to the router. Usually a UTP Cat.5e cable (SFT or FTP are also good but kinda overkill).
Now all of this sounds simple, but the real question is which type of infrastructure will the ISP use, coax, copper pair, fiber optics...
Also, as far as I know, all ISP have a flat rate internet service so it doesn't really matter how much you download or upload. As far as the bandwidth goes, somewhere around 10Mb/s will be just fine for gaming. Ping is a bigger concern, anything above 40ms is too much for stable gaming if you ask me.