While I generally agree with Chunker21 above, and the dealer should have walked you through it during the PDI, getting an appointment at an RV shop may take months. So, here is how to do it:
The silver valve is a three way type and is used to switch the suction of the fresh water pump over to the antifreeze inlet fitting. All you need to do is return it to taking suction from the fresh water tank by turning it 1/4 turn. See the attached pic. The red arrow points to the valve and the yellow arrow points to the antifreeze fitting.
The blue valve on the white pvc pipe is to drain the fresh water tank. Turn its handle 1/4 turn so that it is cross wise to the pipe.
You may also have hot and cold water line drain valves. See where the blue and red tubing goes as it leaves the fresh water pump or the water heater. If you see a silver valve then turn that one so its handle is in line with the tubing. The other position drains out the bottom.
Find the hot water heater. On my Axis it is behind the furnace return air grill. Turn the bypass valves so the handle is in line with the inlet and outlet to the hot water heater. Do this even if you have a tankless heater which doesn't require bypass, but Thor adds them anyway.
Now that all of this is done, fill the water tank and start the fresh water pump and open each fixture- hot and cold for a few seconds until you see clear water flow.
This explanation took longer to write than to do it