(EA) mastery points
The most concise tip I can give you is to google for Dulfy Verdant Brink, Dulfy Auric Basin, etc, and click on the results that mention mastery/achievement guides. She has videos separated out into timestamped sections showing how to get to each communing or chest-opening mastery point. She also has guides on how to get various achieves that give mastery points.
That’ll cover you for HoT MP (including in the 5 new maps). For core MP, you should look through your Achievements panel. Anything with a red MP icon near it holds an MP for you. The wiki and/or Dulfy will tell you how to get that particular achieve.
The reason you need to do this rather than being led to things is that once you have the MP from something, it no longer tells you in your Hero Panel that it gives MP. So if for example I were to try to lead you around, since I have most of the MP already I’d have to constantly ask you to check your panel, tell me what still has points, do my own wiki/Dulfy lookups to remind myself where to go, and it would take you longer to get the points than just looking them up yourself and then perhaps asking for help with specific ones that need a group.