First we need the manilla cardboard for the spine of the cover. Grain direction should be correct as always! The height will determine how big your cover is, so you want it to be at least the distance between your headbands. The width is up to you, often I find the width of one page is a good guide.
Fold the manilla at a point approximately in the middle then wrap it around the spine and find the placement of the second fold by eye.
Once satisfied with your manila spine, you have to cut the greyboard (thick card), I chose quite thick board for this book for durability, quality and protection.
GRAIN DIRECTION APPLIES! It is very important the grain is going the correct way. It's very easy to find the direction in board, use the feeling method, it's virtually impossible to bend board against the grain.
The height of the boards should be that of the manilla, the breadth is optional depending on how much over hang you want. The page width minus a few millimetres is often a good guide.
Ok we need to stick the greyboard to the manilla. Come out from the fold about 5-10mm. I think I did 7 or 8. Mark it with a pencil or pen. Then, get your board ready and spread glue from your mark on the manila to the edges. Then place the board carefully, if you do this badly the cover won't be straight.
This step is optional. If you do this the inside cover of your paper will be smooth, if you don't there is a chance there will be a line resulting from the edge of the manilla. With thicker papers its less important. Grab some sandpaper after the glue has dried, and wear down the edge on both sides.