Welcome to the forum birish21
I'm not sure why you want to go the liquids only route but that's your business. It's your camper, your rules.
I have no need to carry a full fresh water tank but I always have at least 5 gallons or so in the tank to flush the toilet and hand washing while on the road. You could carry water containers to pour into the toilet and hand washing if you wish but that defeats the purpose of having the system you purchased.
ALWAYS keep a little water in the toilet bowl in order to keep the seal wet. About an inch or so. This is while on the road, camping or during storage. NEVER let the bowl seal dry out.
Enjoy your first trip. You'll learn a lot and maybe change a few rules as you go.