Honestly, most people don't really add Adobe Analytics that way.... I can't think of any step by step guides for this... Adobe's tag manager (Adobe Launch, or Adobe Experience Platform Data Collection) is a more powerful tool than GTM, and lighter weight... plus it will manage the Adobe JS files for you, which GTM won't....
But, if you are really adamant about using GTM for this purpose, you will need to look at how Adobe is implemented "locally" as the same sort of code would need to be use.
You will need to download and make all the necessary changes to the AppMeasurement.js file and get that added to the site. Then you will need to review the code syntax of setting all your dimensions and metrics
s.pageName = "Example page";
s.eVar1 = "Example eVar";
s.events = "event1";
Then you will need to manually trigger the Page View tracking call
Or the "Action" tracking call
However, most of this documentation is high level now, as using JS to implement your sites isn't really the preferred method... I don't see any documentation here outlining the differences required for setting up action tracking....
Honestly, I believe this direction for implementation, particularly since you are new to Adobe, is going to cause you a lot of grief.... There isn't a lot of documentation around for this type of implementation, and its a more complicated route....
I highly encourage you to re-consider the use of GTM, and implement Adobe Launch to save yourself a lot of effort and headaches.....