Step 4: Folding!
If you hadn't noticed already, Papercrafts are the 'net' of the shape they will soon be. To get them to their shape we need to fold down every side, for example, above, in the picture every line highlighted in red should be folded in. If you folded it right, you should be able to hold the box together, like i am in the second picture,
After you fold a few folds, it'll be a lot easier to see how the rest fit in, and soon you'll end up with a box ready to glue!