creating a form tab in a private channel

Hi, 

I have created a flow which automatically add a private channel to Teams (Using Graph API) after a user updates a field on Opportunity.

After creating this Private channel, I woul like to add a tab to this private channel. This tab should include opportunity main form. I’m using a HTTP Post request for creating this tab, but as you can see in the following screenshot, I need some information in the body like ContentURl, websiteURl, and the TeamsApp address: 

Does anbody have an idea, what kind of information should be written in the body there?

Thank you!

Best regards