Most slide rules will do many operations, but the basic operation is multiplication.

Multiplication on a slide rule works because you can turn multiplication into addition with

   X * Y = 10 ^ (log(X) + log(Y))

(Edit: i had e and ln up here, but 10 and log is a better match the slide rules from 1 to 10l

The rules are log scaled, so you find X on one rule and line up 1 on the other rule, then look at what number on the first rule is where Y is on the second rule.

Run a couple examples you know the answer to, and you'll get it. As I recall, wrapping/bounding is tricky, you might need to reverse X and Y or go the opposite way to get your answer.

You'll need to do it like scientific notation as well, the rules only have numbers between 1 and 10.

Division is inverted multiplication, so for X / Y, line up the rules so X and Y match, the quotient is what is on the X rule where Y is 1.

I don't know much about woodworking, are you doing multiplication or division with fractions, or adding? Do you want fractional results or decimals?