This is worth so much more than 12 bucks.
https://www.wheelpro.co.uk/wheelbuilding/book.php
Since you can borrow a Turing stand and tensionometer, for for a rebuild with all new DT Comp spokes and brass nipples. Measure your rims and hubs like Roger suggests. I just built a wheelset using one of the spoke calculator sites that had my hubs listed and the hub diameter was dyslexitized to 54 instead of 45 and my first attempt on the rear wheel had the spokes too short. Measure twice.
__________________
I don't do: disks, tubeless, e-shifting, or bead head nymphs.