If there aren't any connections on the back of the compressor, then the compressor ought to run, just by default.
Check the relay up at the top, up near the fuel pump relay. If that's good, you might have to dig deeper.
Edit -
Wait... Where did that compressor come from? The stock compressor has two switches.
That being the case, you should have the connectors for those switches, hanging behind the compressor, someplace.
You should be able to jumper one of those connectors to ground (I think the small "pin" connector) and the compressor should work.
You need to add that switch (at least the high pressure switch) and the appropriate connector, to protect your system.
Sorry. See the post below.
[This message has been edited by Raydar (edited 10-23-2020).]