Quick answer: Collections let you run multiple lists within your wishlist, like one for streaming gear and one for your birthday.
Setting one up
Select "Add Collection," give it a title (a custom image is optional), then pick a collection whenever you add an item.
Who can see a collection
When you create or edit a collection, you choose how visible it is.
Public collections show on your wishlist for anyone to browse. Unlisted collections aren't listed as their own section on your wishlist, so people generally find them through a link you send. Private collections are just for you. Hidden collections get a small lock or link badge so they're easy to spot.
Collections you already made keep the visibility they had, so nothing changes unless you change it.
Sharing a collection
Each collection has its own shareable link. Just open the collection on your dashboard and choose how you want to share it.