I need to set up a land line to provide additional stability and bandwidth. How do I do this?

I am not sure what you are referring to as land line.. in normal terminology that means a phone line.

But for ethernet connection you simply use ethernet cable.. plug it into the LAN ports of the TC and to the computer or other devices.. ethernet is available in various lengths in any computer store.. but for long distance it should be properly installed in the wall using a solid core cable.