Welcome to the forum, and for diving right into the pool!
I guess the first question is, have you hooked up to city water directly and used the plumbing system without the pump and water tank?
The roadside wardrobe is a large closet where you can hang clothes usually. My guess is that it is between your bedroom and the middle of the trailer, on the left side as you face forward. In other words, on the side of the trailer which is behind the driver in the tow vehicle. [sorry if this is TMI -- measure twice cut once]
Here is your manual I believe:
https://www.airstream.com/wp-content...0110i.arc_.pdf
On p. F-5 [PDF p. 78/246] the plumbing section starts incl. the pump and roadside wardrobe language you quoted. The 34' center bath floor plan is on p. F-22 [PDF p. 95/246], but there is no roadside wardrobe so I am thinking you have a different 34' model. Where is your bath, and is there a roadside wardrobe/closet?
The best bet might be for you to check out the above, fill in some details, and let further advice fall into place.
Good luck!
Peter
PS -- Sounds like your A-B-C bypass valves are in the correct positions.