I know, "THE FIRST TIME IS ALWAYS DIFFICULT"! but it helps if you read the instructions.
You are hooked to the black water flush. Some of the decals appear to be missing so neatly cut some white duct tape and mark all unidentified positions with a black felt marker pen for future reference.
Reread the owners manual instructions in the previous post #13.
On the upper left of your service panel is a valve the says -- "TURN VALVE TO FILL TANK"
Hook up your water hose to the street water inlet, not the black tank flush and, to fill the tank, open the valve. To use street water pressure, leave the tank valve closed and the pump off
I see you are missing your hand held shower wand. For your information, this is a standard hand shower available at any hardware store.
The service bay on this and most motorhomes today have both the fresh water and the sewer water in the same bay. I am not a fan of this because of the possibility of contamination. Airstream had a better idea with the Class A CLIPPER, where the fresh water bay was completely separated from the the sewer bay. No chance of contamination.
Be safe and keep you fresh water area clean and take care not to splash sewer water near your fresh water inlet. A spray bottle of bleach might be a good addition to store in that bay.