I think starting with what @squeek502 has linked is a good idea, watching the talk and digging into the Android Template.
Personally I haven’t tackled Android yet, so I don’t have a lot of practical things I can recommend, maybe you can find some thing related to it in one of these lists:
I am not really aware of any courses or teaching material available for porting things to android. To me it seems like it is mostly a matter of getting your hands dirty with it and finding out the details while actually getting a project to work.
There are probably a few good blog-posts that describe the most useful steps and resources, but I haven’t researched that yet. Currently web-assembly has higher priority for me, I also wondered whether wrapping a web assembly app into an android application would make sense, but I suspect that it would have much worse performance then using ndk directly and use that to build an android app.