1. Tap    in a message room.
2. Tap 'Event' to open Event.

You can also open the Event by swiping left on the Note screen.

1. Click  on the top.
2. Click a message room from the message room list.
3. Click the 'Event' tab on the right side of the message room to open Event.

1. Click  on the top left.
2. Click a message room from the message room list.
3. Click  on the top right of the message room.