After all of the lumber is ready, you're now able to cut your main supports to size and start assembling them. I started out by first making a square with 4 planks about 5 and 1/2 feet tall. Each short board was about 15 inches long. I nailed the short 15 inch boards so that I would have 1 foot of space from the bottom of the above plank if that makes sense... basically I measured from the bottom of each short 15 inch board and marked 1 foot down. The next top would be placed on this mark. You will need 2 of these for the left and the ride side supports.
Your third support, which is the middle support, will have short planks (15 inches long) on both sides of the long planks.
Once your supports are made up it is now time to start putting your main shelf pieces together. I made my main shelves 30 inches long. You will need 4 of these per shelf. You can start with the left or the right, but you will need to take your middle support and your left or right support and begin nailing your shelves onto their support planks. I started with the outer shelf pieces on the top and bottom, then filled in the rest after.
After nailing your shelves into place, you do not want to the shelf up, it will topple over one way or the other, you need to nail your back bracing on first. I put one back brace per shelf right below each row of shelves. I made the top of my bracing flush with the bottom of the back shelf. Assembling this part is easiest laid down on its face.
(Note the first set of bracing I assembled was only the length of the first half of the shelf. The same will apply with the other side once you put it together)
You will do the same for assembling the other side, once finished you should have this built....