Vacuum pump wiring question ?????

Ok,I have a (GM)Delco vacuum pump,like SSB used to sell.The positive and negative I get.Trying to figure out where to wire in to the ignition so it only gets power when the key is on.

So far I've tried wiring it to the top post on the starter relay...it comes on,shuts off,then comes back on again,whether the key is on or not.
I have a fresh rebuilt booster,so does this mean the booster is bad?
I am not very experienced with wiring,am I just missing something here?

Thanks!