Brochure fold you paper twice. It should be divided into 9 sections.
Next, bring the bordering lines together like so.
This is what it should look like once you do all the sides.
Next, take the folded tabs and bring them together. Fold down the excess.
Your box should now look like this.
This step is optional. If you want to make your box more secure, rip two slits about an inch or less in the middle. Fold it down. It acts as a staple.
This is your final product. Congrats!