Draw a simple top-down floor plan — doesn't need to be perfect. Label walls A, B, C, D. Mark windows (W), doors (D), and where your sink, range, and fridge currently are.
Label each wall A, B, C, D going clockwise. Mark windows with a double line, doors with an arc. Mark existing plumbing location (sink drain).
Mark gas or electric range location. Write measurements on each wall directly on your sketch.