Step 2: Make your Measurements
For each stand, you'll need four roughly equal pieces. If you want this next to a wall, you could do one shorter, or whatever. I measured out my boards and figured I'd cut to about 15 inches for each piece. This wound up being more than sufficient for my purposes. The taller you're going, the wider your base should be.
Measure your boards, and use a T-square, or in this case, the edge of my miter box to draw a nice straight line.