How can I join a specific group?

[Mizu]

Hello everybody
I wanna join a group,there is no button or a section for it!
I searched the name of the group, and there is no result!
(I found this group from one of my friends' profiles)

[Renske]

This is not a librarian question, the help section is the right place for these kind of questions.
But a possible reason is it might be a private group where only the moderator(s) of that group can invite new members.