This guide shows how to make the Deimos C Class Battleship from my ship building guide: I cant put links here apparently so just search “All Ship HAB interiors“ on google and the reddit post should pop up :)
most parts are available at Deimos Shipyard around Mars. for the hopetech hallways you need to go to hopetown and check with the sales person inside. i recommend placing a single 1x1 hab inbetween the engineering bay and the ladder shaft leading to the cockpit as a placeholder, the side ones can be left empty, until you go to hopetown to pick them up. I bought the engines at Akila.