If you can post a picture if your oil pressure gauge and the "wiring" that came with it we can help.
They come in two ways: with an electrical and mechanical. Electrical sends a signal to the gauge through a wire attached to the sending unit on top of the block beside the distributor (see pic). A mechanical gauge has a hollow plastic or copper line that runs oil from the sending unit to the gauge. Which means you will have oil pumped to the gauge inside your car! I always use a copper line in hopes it won't crack and send oil gushing into my car.
Edit: I just had a closer look at the picture I picked off FABO and it looks like this guy is running both, electrical and mechanical. You can just see the copper line at the bottom of the sending unit.
View attachment 1716102804
