electric fuel pump with stock gas tank

Hi guys, I have installed a electric fuel pump and the filter with the stock tank just above the rear hosing, but no pressure build up ? Any ideas what is my problem ?

I have Jegs electric fuel pump kit with filter and all 8AN braided hose from front to back. Everything is new, do I need to prime the pump first to be able to get pressure and fuel at carb....

Thanks for your help.

dumb question: do you have enough gas in it? When i did mine, i had trouble maintaining pressure because the gas was too low. Especially with the car in my driveway