How to hook up different GPS units to pixhawk

Hello all.
I’ve got a GPS hard mounted in an airplane I’m converting to Pixhawk and AP 3.9.2, and I’d like to use it with the original pixhawk. Can this be done? I found the pinouts and the protocol elsewhere, but I need help that’s more idiot/newbie level. What to hook to what? It’s an early Eagle Tree unit.
Or is it not worth the effort?