A remodeler will look at the floor framing, the drain location, and the existing valve, then talk through layout, glass, and curb height. In Hanover, expect questions about your water, since it affects grout and glass choices, and about your septic system if you want more than one shower head.
Permits for the job are filed through Hanover's OpenGov portal. The plumbing permit covers the valve, supply lines, and drain, and an electrical permit applies if the plan adds lighting, a heated floor, or a new fan circuit. The Town's plumbing and gas inspector should see the rough plumbing before walls close.
Before tile goes on, ask the crew to flood-test the waterproofed base and let you see the result. A pan that holds standing water without the level dropping is the clearest sign the hidden layers were done right.