Okay Pamela, many of your pics are showing.
The hoses appear to be connected correctly on the sand filter's MPV at the top, so I think you're okay there (for now). But here are some things you should probably check or consider:
1. Since you "inherited" this pool, I suspect the pressure gauge may just be bad. It can happen with any gauge, especially if it was out all winter. So you should consider a replacement like one of the gauges
HERE. Very good quality and reasonable prices. Let's hope that resolves that one.
2. About the lack of water flow, let's remember that with an AGP, gravity is your pump's friend. By that I mean water should fall-down effortlessly from the waterline a few feet above the ground, down to the pump below. The only thing in the way appears to be that valve with a PORT 1 or FULL selection. Not sure about that one, but experiment I guess to see which works best to ensure water flow unimpeded to the pump.
3. Make sure the water is up at least halfway in the skimmer opening and that the weir door (flap) is moving well and not stuck. You should feel pretty good suction in that skimmer if you place your hand over the suction hole.
4. For the pump, remove the clear lid and check the O-ring underneath. Make sure it's not cracked or anything. If it's good, make sure it has a generous coating of pool silicone lube on it. That's very important to avoid a "suction air leak" (like drinking from a broken straw). If the pump has a drain plug at the bottom, remove it and check that O-ring as well. Before removing the clear lid or O-ring you'll need to stop water flow from the pool, so close that valve or stick something in the hole in the skimmer.
5. Check those hoses
really well. They can crack or get a pinhole very easily and not really leak water out, but they can let air "in".
Let's start there and we'll move on to more troubleshooting later if you still can't get water to fill the pump strainer pot to the top of the clear lid.