Here are four of my favorite online resources for quickly getting up to speed in Microsoft Power BI:
An excellent quick overview of the software from beginning to end, including a number of little details and power features to be aware of in case you need them down the road.
Once you’re up and running, you’ll find that you need to create calculations, complex custom filters, etc. DAX is Microsoft’s language for this. This LinkedIn Learning video series provides an excellent way to get familiar with DAX and how it works.
An outstanding intro to how to get serious about learning DAX and working with it in earnest, including with the uber-helpful DAX Studio to help with composing and testing DAX code.
This more in-depth LinkedIn Learning course walks you deeper into a number of intricacies of the software and how best to use it to accomplish desired tasks. The video series has several chapters, from which you can pick and choose depending on your needs.
Then of course, the Microsoft documentation and reference resources are a must: