ETA: To get the film back into the roll without exposing it, simply take it into your closet (any completely dark room) when you have finished the roll, open the camera and push the film back into the camera by hand (it's easy) OR take it to your photo lab (still in the camera, of course) and they can manually roll it for you in their dark box!
We hope that our tutorial has been helpful to you today! This is the most experimental project I've done here. Lots of things need to be learned through trial and error (most of all film rotation techniques!). There are tons of great resources (other tutorials, youtube videos ect) all over the internet if you have any questions or need more clarification. There is more than one right way to build a pinhole camera. In fact, every single camera will be at least slightly different & that's the beauty of it! Feel free to take this basic information and translate it for your own lovely custom camera. ♥