The SQLBI youtube channel is a great place to learn about all sorts of DAX and Tabular engine topics. They also have a playlist of short videos dedicated to DAX Studio as part of their DAX Tools courses.
The following 4 videos are from a series produced by PowerBi.tips in 2020. You can checkout these videos and more great Power BI content on their youtube channel.
1 of 4 PowerBI.Tips - Tutorial - Introduction to DAX Studio - Darren Gosbell
An introduction to DAX Studio, from downloading and installing to running basic queries
2 of 4 PowerBI.Tips - Tutorial - Model Performance Tuning in DAX Studio - Marco Russo
An overview of using DAX Studio to optimize your tabular models.
3 of 4 PowerBI.Tips - Tutorial - DAX Studio Full Feature Review - Darren Gosbell
A full feature review of all the important features in DAX Studio (as of the 2.10.2 release)
4 of 4 PowerBI.Tips - Tutorial - DAX Studio Query Performance Tuning - Marco Russo
A tutorial on how to tune your DAX queries and measures using DAX Studio
DAX Studio 2.7 - improved debug experience
This video introduces new features that improves the debug experience in DAX Studio: tooltips for columns statistics, capture trace of all queries, and definition of dependent measures.
DAX Studio 2.1 - analyze query plans and find bottlenecks
DAX Studio introduced important features to analyze the query plan and find bottlenecks in your DAX code