First, you do not need to install any software or drivers to be connected to a router. I'm not sure what you're "installing", but it's not necessary and sounds like it's only further confusing you.
Second, if you want to share internet access with all computers, you have to connect the modem to the router using ethernet. There should be a port on the router labeled "WAN". This is where you connect the modem. Once all computers are connected to the router, they should all be able to access the internet.
If you want to share files, that becomes significantly more complicated especially with multiple operating systems. If you want to do this, ask, but be prepared to put in a lot of time to get it working. It could take days or weeks to accomplish it.
Second, if you want to share internet access with all computers, you have to connect the modem to the router using ethernet. There should be a port on the router labeled "WAN". This is where you connect the modem. Once all computers are connected to the router, they should all be able to access the internet.
If you want to share files, that becomes significantly more complicated especially with multiple operating systems. If you want to do this, ask, but be prepared to put in a lot of time to get it working. It could take days or weeks to accomplish it.
