Try it!
Create and format a post or announcement to start a conversation in a channel.
Note: The following steps are current and may be out of sync with the video.
Select the New conversation button.

Type a message.
Select Format
.To create an announcement, select a post type > Announcement
.
Type a headline and an optional subhead, and then add a color scheme or your own background image.
Format your post including the following options:
Add a subject
Font size
Bold
Bulleted list or numbered list
Insert link
Select Send
.
Tip: To make changes to a post or announcement, select More options
> Edit
.

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