You can share a page into a channel or a direct message on Slack either from the Tettra app, as shown below, or via a slash command from inside Slack.
The first option is to click on Share when you're on a page.
The second option is to click on the kebab menu in a category or subcategory view and click Share on the menu that will appear.
Select Slack on the pop-up that will appear, choose the channel or direct message you'd like to share the page in, and click Share page. Optionally you can also add a message.
Once you've shared the page, it will show up in Slack like this:
