In order to prime the filter, have the intake pipe set up in the tank, suck on the output hose (disconnect it from the spray bar if you are using one) and wait for the tank water to fill up the filter completely. Be sure the output hose is above the tank water line so all the air can escape from the filter. Reconnect the output hose to the spray bar and then plug the cord into the wall outlet.
Are you using the quick disconnect fittings with the filter? If so, what I do is make sure the output Q.D. fitting is closed, open both valves of the intake Q.D. fitting, place an empty 5G pail next to the stand, and point the output Q.D. fitting into the bucket, open it, suck on the end to get the water to start entering the filter. Once I have a steady stream of water, close the output Q.D. fitting, connect it back to the other Q.D. half, open both output valves and then plug the filter in. Doing it this way won't require you to mess with the spray bar hose connection.