How do I view & use Collections?

Somebody from another posting told me about adding movies to Collections, which I then did. Now I can’t find how to view or change my Collections. I tried searching the forums and, besides other peoples’ issues, the only link was the following which only tells how to add items to a collection.
https://support.plex.tv/hc/en-us/articles/201273953

I’m unable to find how to view/edit my Collections once they’ve been created. Can anyone point me in the right direction, please?

Thx!

Collections are just another type of label you can attach to any of your media items.
You modify them implicitly, by editing your media items.

You can filter your library for them.
They are also used to generate a ‘related movies’ ‘hub’ in the newer Plex clients.