You can join or create a Group with others on Bookwyrm. There are many things a group could be made for - a book club, a bunch of friends, whatever makes sense for you. Groups can curate book Lists together, but that's about it right now. Currently, the Bookwyrm developers are focusing on other things, not groups, but they will be improved in the future.
To find the groups page, first navigate to your profile, then open the 'Groups' tab.
On the top right of the groups page is the 'Create group' button. You will then need to give it a name and describe what it is about, before choosing its privacy setting.
Groups have the same privacy settings as posts and lists do, except they can't be Followers-only. Group membership always requires an invitation from the group's owner, even if it is marked Public. For more details, see here.
Groups are currently limited only to members on the current instance. To add members, search their username in the search bar, then click 'Invite'. To remove members, click the 'Remove' button and then 'Confirm'.
To join a group, you must be on the same instance (website) and be invited by its owner. You will then receive a notification which lets you join. The group owner is marked with a star symbol.
Group Lists work very similarly to normal Lists, except they are curated by all members of a Group. They can be created by any member of a group from the group's homepage.
Allow users to request to join public groups (#1840 on GitHub)
Allow groups to have multiple admins/owners (#1841 on GitHub)
Allow groups to include users from multiple instances (ActivityPub) (#1548 on GitHub)