If you want to set up a group chat in Google Duo, its easy to do.
First, choose Create Group at the top of the screen.
Tip: On mobile, the Create group button can be found at the bottom of the screen.
To create a group chat, tap the Create group button.
Alternatively, you might copy the invite link by clicking the copy link icon to the invite links right.
Then share it with whoever you want to join.
Group chats in Google Duo can only have up to thirty-two people, including yourself.