Instruction:

Step 1: Search all your material together. Good to work is a big table, but if you don't have one that is big enough try to work on the floor ^-^
Step 2: Spread the pattern out of the floor/the table. Lay down a part of the foil that is big enough to copy the parts of the pattern with the foil pen onto the foil. Look at the instruction notes of the pattern to know what parts and which size you need. You have to copy everything, all the signs, all lines and notes. These are important hints when you're sewing all parts together later.
Step 3: After finishing to copy all the parts of the pattern you need onto the foil you can cut it out. That's the easiest part ;)
Step 4: Now you have the parts of the pattern in your size. You can pin the foil parts on the fabrics and copy the pattern onto it with some chalk or a simple crayon.

Notes: There are some cosplayers saying they can't use pattern because it's to Acomplicated (which I can't really understand). I like using pattern because they are easy to handle.
Please note that this is my personal way of using pattern. The instructions tell the user to cut the pattern out in the right size... which I don't like because I can't use the pattern later again or change it easily. That's the reason why I'm using the foil. ^^