wiring in electric fuel pump

[72blue]

Hello all. I am new. I have a 72 K10 that i have been restoring and have reached the wiring. A holley red fuel pump is installed and I have a M&H harness for the rest of the pickup. I have read about other members that have had problems with their engines not shutting off after they have installed a relay with their electric fuel pump; as this might be just a installation error, I would like some direct input. What kind of relay do I need; single post or double? What is the difference in this case? Where should I locate it? I would appreciate any knowledge. Thanks, James