Well, the product is yours and I'm sure you'll find something good to do with it. Maybe You already manager how ro clean up the brown poder but I think a brush would be helpful.
I would put the brown pieces into another container, I think there is no way you can put all that together.
Probably the members of that class and the teacher think of it more like a club where they can spend time practicing previously known techniques.
With a brush you smear out the brown everywhere it's not dry powder. I pressed a part back into the empty place and tried to wipe of a part with toilet paper but it takes away more of the other colours. In the future I will think out how to use it... Some BarbaBob art might be an option. 🤣
Ha ha ha, You can create it yourself, or simply experience the nuances that the messy powder brings; something good might come of it.