1. Open the WeChat application and enter the Address Book interface.
2. In the address book interface, click the+sign in the upper right corner, and then select "Join Group Chat".
3. In the "Join Group Chat" interface, you can search and join a specific group chat through the "Group Number" option.
4. Enter the group number to search for, and then click the "Search" button.
5. If you find the corresponding group chat, you can click the group chat name to enter the group chat page, and then click the "Join Group Chat" button. In addition, you can join the group chat by building a group face to face, scanning the group QR code or inviting friends.