Summarize the following:
You should be able to find one at your local art supply store.  If you have a piece of paper that is larger than 17 by 18 inches, simply cut it down to size. Construction paper works well for making a folder. You can also use a stronger type of paper, such as a thin cardboard or poster board, if you would like the folder to be more durable. If you don't have any paper that big, you can simply tape pieces of paper together to make one that is the right size. Place one of the short sides closest to you and the longer sides running up away from you. Fold the bottom 6 inches up and make a crease along the fold. Make sure to fold it so that the longer sides are folded but the shorter sides stay the same length. Be sure to fold the paper right down the middle. Fold the paper so that the previous fold is concealed inside. This will make the pockets on the inside, instead of the outside. You will only need to attach together the outside edges that have two layers of paper, where the long sides were folded up, and the center crease, where there are two layers of paper due to the pocket flap. This will finish the pockets on the inside of your folder. Remember to to do this step on both flaps of the folder. Personalize it with decorative flair or simply write a description of what you will keep in it, so that you know without having to look inside it every time. Now your important papers are safe and sound in your very own homemade folder.

Summary:
Get a piece of paper that is approximately 17 inches tall and 18 inches wide. Fold your piece of paper to create a pocket. Fold the short sides of the paper in half and then crease it. Staple or glue the edges to finish the pockets. Decorate the cover as you please. Put documents inside your new folder!