I am assuming that when you introduced Hive to these school kids you thought them "how to" use Hive. In other words, you are teaching them how to "DIY".

For full guidance on when you can use #diy tag, refer to this post.

Your post need not be immediately related to DIY creation. It can be remotely related to DIY creation. Therefore, say you are visiting a DIY store to buy something to repair a pipe in your house, a post on your visit to the store can use #diy tag. Your post on your visit to the store is not not the DIY creation itself but is remotely related to a DIY creation, i.e your repair works.

Hope this helps.