.................a scary place, but welcome!
When I plan a project I resort to my own system of primitive sketches. There are all kinds of worksheets available for figuring out stuff like this, but in the end I go back to my own sketches. After the job is done I keep the notes and drawings with the order.
Here are a worksheets for a few recent orders.
I need to have every bit of information all on one sheet, in my own shorthand which I can instantly understand, even if it's gibberish to anybody else. I get worried when it's gibberish to ME!