You can read more about this new feature here. But the long of the short of it in beta phase is this:
- Maximum amount of 5 tags allowed per post.
- Tags will sort your user posts only and don't apply to other user's posts.
- Some tags will be auto-generated for you, mainly your Reward tier tags by Pledge amount and Public/Private posts. (See the screenshots below)
- Patron-Only posts are blank when displayed in tag feeds where a user is not a Patron. (See the screenshots below)
- No way to tag multiple posts at once.
Here's how the tags currently look on my art Patreon. The archive of all tags used shows up on the left. You currently cannot toggle this archive list on and off: