air solenoid setup for relay

Hello, I did lots of searching but came up short so any help given would be great. I have a air solenoid that is normally open so air comes out of it constantly. What I need to do is supply it with a constant 12 volt so it stays closed to I need it open, but I am having a hard time figuring out how to wire the relay. Its been a while since I messed with this. Thank you

Battery to terminal 30, 87A goes to the positive wire of the solenoid.  When the following condition is met, the air will flow.  Ground on terminal 85 and positive voltage on 86.