Using cardboard walls is a cheap & light way of sectioning off areas of your building that you don’t want used during your youth program. To get large pieces of cardboard like the ones pictured below you can either buy large sheets of cardboard from a cardboard factory, use fridge boxes, or glues small pieces of cardboard together.
Once you have sourced out the cardboard paint them black and put a fold in them every few feet so that the can stand up on their own.