Squarespace help

I know there's a way to add tags & categories to my Squarespace site so users can filter and sort the directory but I keep hitting deadends. Apparently you can add tags and categories to a gallery, so I made gallery, but I don't see the tags anywhere. I think Squarespace is using confusing terminology here-- you can add a gallery "block" or a gallery "page" and maybe it's the page but not the block that you can add tags to? HELP!