Find the founder of WeChat group and let the founder join the group (if you know people in the group, you can).
You can also build your own WeChat group, click the button in the upper right corner of WeChat, select Start Chat in the drop-down list, then check the friends who need to join the group, and click OK to build the group. (If you need to add friends, you can promote the QR code of Guangfa WeChat group. )
By scanning the QR code of WeChat group published by others to join WeChat group, you need to go to some places where WeChat group is displayed, such as WeChat group sharing.
If you have joined a WeChat group, you can ask the group members who have a WeChat group to pull it. Of course, if there are two groups, you can shout to change the group in the group, let others join the group, or you can pull others into the group.