Absolute beginner's question

I find your tutorial uses too many defaults, without explaining them.
I want to draw a bookcase, and just need help getting started, just to draw 1 upright. If I can do that I can do the rest.
The material is wood.
The upright is 2.070m high.
The depth is 0.150m.
The piece of wood is 0.020m wide.
I need detailed steps to do this.
Having drawn the upright, I need to make a cut at the back to accomodate the skirting-board.
The cut is 0.080m high and 0.020m deep.
Need these steps as well.
Thanks,
Nigel