Good point. I'll mark this as an enhancement to add a section about ad playback in general.

I was trying to understand how to use AdsMediaSource today as we are currently building a large podcast app (1M+ users from our existing user base) but no such luck :-( Can you point me to some info/examples etc ? Many thanks

The original blog post about the IMA extension still has some useful information and may be a starting point. The ExoPlayer demo app also integrates with the IMA extension so you could take a look at that as well. Resolving this issue by adding proper documentation to the developer guide is still work in progress I'm afraid.

Edit: given your issue #6891 is a different use case from the IMA extension, this answer isn't relevant. Please have a look at #6814 which I think does what you need.

There is a section on ad insertion now, here.

Thank you for following up @ojw28!