What are the best DAX/Power Query/M Language training resources available?

I find myself struggling most when it comes to creating custom DAX/Power Query/M Functions. This community has been a true blessing as this is my 2nd full month working with Power BI. I purchased a few courses on Udemy for Power BI and there are a few references to DAX on there but nothing that can be as transferrable to what has been provide to me in support from you all as a community. I mean the level of complexity of the DAX functions that have been provided in support to me has been light years ahead of what I am currently learning. 

Where did you get your base training? I know that as I keep working with DAX and Power BI, things will start to get a little more familiar. The best form of training for me has always been a guided visual/video tutorial. If you all know of any that will give a solid foundation, it will be greatly appreicated! 

Thank you all for the support because you have come through in the clutch for me!