You’re in luck. Enterprise DNA Expert @haroonali1000 led a Problem of the Week earlier this year focused on this exact issue. If you go through this thread, it will have his writeup, his solution and solution video, as well as a bunch of other solutions (with PBIX files) from other EDNA members and experts. I’m confident that these materials should have all the info necessary to meet your requirement, but if you still run into any problems, pl;ease just post an updated work-in-progress PBIX file and highlight where you got stuck.
Also, here are a couple of videos responsive to the second part of your question. For learning M, I cannot recommend EDNA Expert @Melissa’s videos highly enough - I think they are truly the best resource on the internet for learning Power Query and M code:
Another great resource is Gil Raviv’s book on Power Query and M, which I think is by far the best book available on this topic. It has an excellent introducton to writing M code.
Finally, here’s a video I did recently that provides an introduction to the “Learn by Googling” appproach to M code that I learned from Melissa and have found enormously helpful:
I hope this is helpful.
- Brian