I got lucky

Turns out it was just the fuel pump relay. I switched the two relays in the glove box and it fired right up. Not sure what the other relay was for, so now likely someting else isnt working, but I will be getting a new relay shortly. I got the Blazer cheap cause the guy I bought it from through it needed a fuel pump but I got lucky .

Today I will have it on a lift to check a leak (oil?) and change the oil as well. I also have to check the headlights as they weren't coming on and either the battery or alternator has a problem (I charged the battery like 3 times now but only drove it around the parking lot).

If I have to change the fuel pump in the future, I now know where to look for some information. Thanks for your replies.