I had issues with my pump, and the ring had been bent. Getting all the tabs to connect was a bit difficult. Get one of the tools like in the video. They may sell some universal ones on Amazon. I made my own out of bar stock, welded up and helped push down on the pumps spring that pushes up. A big guy in a confined area was tough (roll bar, remove race seat, etc.) Passenger side has the siphon hoses I think, the driver's side has the pump.
My car had too many people that had bounced in the rear seat and that ring had been off once before, kind of bent and had to wait and order another one. And yes, gas vapors, it was hot out and had to have doors open.
Funny story I read about a dad that had bought his daughter one of these Mustangs and twice left her stranded when it would not start. Mechanic showed that some kind of (ahem) activity was on top the back seat and working the electrical connection off, thus the car not starting. I am sure this is an "Urban Myth".