Short answer: Collections help you group related media and optionally present public sets on your profile.
Steps
Open Library or a media detail page.
Create a new collection or choose an existing one.
Add images or videos to the collection.
Edit the collection name, description, and visibility when needed.
Notes
Use clear collection names for easier discovery.
Public collections are best for curated sets, not every draft.
Troubleshooting
If a collection looks empty publicly, confirm that it contains visible public media.
If you cannot add media, refresh the page and confirm the media still exists in your library.