|You shouldn't be installing firmware at this stage. You need fully functioning router to do that. You wont find drivers because there is no such thing as a driver for a router.|
What you do need is a driver for your Network Interface Card but that is installed by the operating system.
All you need is it is connect the Ethernet cable from the computer to the router, and the Modem. Plug in the router to the power and switch on. Configure the Network Interface Card to get IP address automatically and re-boot.
When the computer has re-booted go to a command prompt and type ipconfig. Look for gateway address which will probably be 192.168.1.1. Bring up your browser and enter that address into the address bar. That will give you the routers configuration screen but first it will prompt you for a user nae and password.
See the user manual for default user name and password. When you are in the configuration screen you can then configure router according to the manual.