1. thinking
   1. get ideas from forums, instagram, youtube, etc
   2. consider what kind of amenities you want
      1. bed: material, across the van or lengthwise, dedicated or used for other purposes
      2. storage: plastic bins, milk crates, thrift store dressers, built cabinets
      3. water tanks
         1. fresh
            1. pump: manual, electric
         2. gray
      4. cooking
      5. toilet and hygiene
      6. power: shore, solar, house battery
      7. roof real estate: solar panels, fan
   3. sketch ideas for layout on paper or software
2. mocking up
   1. sit in the space, or measure the space and mark it out in an unused room
   2. use actual gear or cardboard mockups as placeholders to help you understand the layout
3. roof work - this is done early so metal debris can be swept/vacuumed out easily
   1. fan - cut hole, install, leave wiring accessable
   2. solar
      1. install rack or tabs
      2. install panels
      3. install wiring entry point
   3. insulate ceiling
4. floor
   1. cut any needed holes for vents, drains, etc
5. body modification - cut any holes for water entry, shore power connectors, etc. Note: traditionally hookups go on the driver's side of the camper.
6. framing - if you
7. wiring
8. insulating
9. shakedown
   1. overnights
   2. weekends
   3. trips

Ideas taken from