I believe it adds them to your feed. There's also a "followed tags" section in your profile if that's what your looking for.
nostr:npub1vahlaghvx9px4yrdw72a06aw9wj7v8ctn75ptx2mfg5em5y965gqnvm9qh nostr:npub1235sdlh0g02chm8778ka936p9405c2ha4vsnr4y3xvelk0hvjk2s0y20eh I found the follow button. Does it just add a stream of tagged notes to my feed now? Or is there a place where I can follow the hashtag stream separately? Can't find that, if there is. Thank you!