How to install a gas gauge in a jeep Cherokee?

My jeep 1990 jeep Cherokee's gas gauge does not work now that I have a new tank and wasn't sure if I there is a gauge that I could buy that isn't too difficult to install. I'm always up for a project if it's gonna save me money though. The that's in the dashboard kinda worked with the old13 gallon tank but would fluctuate as I drives but now it isn't connected at all. Any ideas?|||first check wiring and ground connections. could be sending unit in tank which unfortunately is part of fuel pump.