Valentine's Day Gift Exchange for Preschool

Okay mommit, help me out here. My husband and I are not from the US, where we now live. We have a daughter in preschool and this morning at drop off we were handed a box to decorate for their Valentine's gift exchange. This wasn't a thing where we grew up and there were no further explanations. I'm guessing we need to decorate the box and fill it with little gifts for the whole class? What is the norm here? Are we talking small things like maybe pencils and stickers? Also, minor argument my husband and I had: do we package each child's gift or just throw everything into the box and hand out one of each item? I'm probably overthinking this but like..... Help?