Now that we have everything measured out we're ready to start putting the bookcase together. We've marked on one side for the shelves and we've come over to the other side and marked another line for the screws. Make sure you've got the right side of the board and lay it down and counter-sink on every one of those lines that we just drew in our last step. So I've already done that on this board. All the holes are counter-sunk and we're ready to put a shelf in. We took a nice board that we like for a shelf. And as you can see, I've put a back stop up here so I've got something to push against. If you don't have that, it's kind of hard to control these boards and hold them up at the same time you're putting in a screw. Now I'll hold these two boards together and get the corners to match. Just the very corner is all you have to have match on this. Now take the screw and stick it in the hole, hold the board together. This is where your hand has to be pretty steady. And drive the screw. It's okay if this overlaps just a little bit. In fact, sometimes you do want that because later we're going to sand this and we'll get a nice flush edge if we've got a tiny little bit, maybe a thirty-second of an inch sticking out. You want to square your board along the edge. And just drive the screw. Now we've got our top shelf in. We're going to continue doing that until all our shelves have been installed on one side.