If you want to the Mobile Service Cloud to handle your Instagram Direct Messaging there's a few steps to follow. The first few steps you can do yourself!
Connect the Channel
In order to receive and send messages from and to Instagram, it needs to be connected to the Business Messaging app.
Navigate to 'channels' and click on 'add new channel'
Select the channel to add (Instagram Messaging)
Select 'Add Channel'
Add your contact details and click on 'request'. This is for CM.com to contact you in case difficulties come up
Done! Now you can move on and start adding the pages.