I've got my father's. Still in the original box. I learned to use a normal linear slide rule at school, but every time I look at this I have to read the manual

I've got my father's. Still in the original box. I learned to use a normal linear slide rule at school, but every time I look at this I have to read the manual to sort out how to use it. I'd like to fix it in my head so I could whip it out at work when calculations are needed. Just for geek points