Meetings, discussions, parties, what can't you use a group chat for?
From the main screen, tap the "+" button in the top right, then choose New Chat. Choose the people you want to invite.
Tip 1: Private Groups
A quick way to make a group chat for a bunch of people together in real life is to create a "Private Group".
From the main screen, tap the "+" button, then New Chat, then Join Private Group. You can enter a four digit code to start or join a group with friends nearby. Now other people around you can type this code to join.
Tip 2：Saving a group chat to your contact list
You can save a group to your Contacts to make sure you can always get to it on any device.
From inside the chat, tap "..." on the upper right, scroll down, and switch on Save to Contacts.
Now, any time you want to get to this group, go to Contacts and choose Group Chats. You should see it listed here.