A stair stringer looks simple until you mark one out and the last step comes up half an inch short. The maths is not hard, but every number depends on the one before it, so a single rounding slip carries all the way down the board.
Start with the total rise
Measure from the finished floor at the bottom to the finished floor at the top. Not the subfloor: the finished surface, because flooring thickness at either end changes the height of the first and last step.
Divide it into equal risers
The IRC limits a riser to seven and three quarter inches, so divide the total rise by 7.75 and round up to get the number of risers. Then divide the total rise by that number for the actual riser height. On a 105 inch basement rise that is 14 risers of exactly seven and a half inches.
Then the treads
There is always one fewer tread than risers, and the IRC wants each tread at least 10 inches deep. Fourteen risers means 13 treads, so 130 inches of run at the minimum. If you do not have that much floor, rethink the stair before you cut anything.
Keep every step the same
The code allows no more than three eighths of an inch between the tallest and shortest riser. People feel a variation long before they see it, and uneven steps are what trip them up.
Walk the square down the board
Set stair gauges on a framing square at the riser and tread figures, then walk it down the 2×12, marking each notch. Drop the bottom of the stringer by the thickness of one tread so the first step comes out the same height as the rest.
StringerPro is an app that works the layout out in inch fractions and checks it against IRC R311.7, then gives you the heel positions to walk a framing square down the board.