There are 2 ways to start group chat:
1) From Chats tab, tap on the ‘Compose’ icon in the upper right corner and select from the list. You can scroll the list or search by name.
2) From an existing chat, tap on the ‘Settings’ icon in the upper right corner and then tap ‘Add’.
You may also invite people to join an existing group by sharing QR code. From the Chats ‘Settings’ page, tap on ‘Group QR Code’. A group QR code will be generated on your screen. Tap the ‘。。。’ to save the QR code to phone, and then you can share it via social network, email, SMS etc.