Your local hardware store will carry screw posts. That's where I found mine. If the shop keep doesn't understand what a screw post is tell him (or her) that you're going to bind pages together. That's how I got the guy at the counter to understand what I needed. The length of the screw posts will determine the thickness of the book. I'm using ¾" screw posts which would give me over 200 pages in my book. I may never need that many pages but I'll never have to worry about running out of space. If you use longer (or shorter) screw posts then you'll have to adjust the measurements of supplies needed. Remember that making the book too thick may cause problems with managing all those pages being held together. The colour of the poster board will be up to you. Black was my original choice for a book cover but I found a nice red (textured) poster board at Michaels Arts and Crafts. Check for a store location near you. You can also purchase the felt fabric here. Again, the colour is up to you.
The paper you pick is extremely important. If you want to write on both sides you need to make sure that your ink doesn't bleed through. I found a good quality paper. It's called Wausau Paper (#49311). You may want aged looking paper if you want an authentic old look but I'm not into fairy tales here pretending to be something I'm not. Always make sure that the measurements (if cutting) are more than you need so you can make adjustments. It's always better to have more than not enough.
These are all the supplies need to make the book. What you need now are the tools. Keep a pair of scissors at your side. You'll also need a hole puncher. The right glue is extremely important to holding everything together. Elmer's glue would make the book bubble. I've had to learn that the hard way. Hot glue is even worse. I used M77 which is a spray on glue. You can find it at your local hardware store while you're purchasing the screw posts. The spray coats evenly and dries quickly so there's not much waiting time. I'm giving you a month to gather the supplies you need. Next month we'll put this thing together.