ok got some questions on air.

im running two Viair 450s, two 5 gallon tanks, and 1 pressure switch...how do i make that work? can somebody explain this to me in full detail...is it possible? if so how do i make it work, do i need to somehow run the two tanks togehter, or am i going to have to get another pressure switch...also how do i wire it to shut off with my car? im running a starter solenoid for the setup, do i need to use the relay? please help me out..first time installing and where finalising it tomorrow.