The new sticker has been released in all countries today, but the feature will be shown to users gradually over the coming weeks in the iPhone (iOS) and Android app.
To use the chat sticker in a story, just add the sticker to the post and post it. Followers interested in the chat should then touch the sticker. The postter can check the requests in the Stories preview section, and tick the right blue check to choose who to chat with. By pressing the "Start Chat" button, the group conversation takes place by Direct.
The creator can end the chat at any time. The tool, which has been under test at least since May, can be a good solution for messaging between groups of friends to organize plans or discuss other punctual issues.