These are my SQL Server Diagnostic Information Queries for June 2020, aka my DMV Diagnostic Queries. They allow you to get a very comprehensive view of the configuration and performance of your SQL Server instance in a short amount of time. There are separate versions of these T-SQL queries for SQL Server 2005 through SQL Server 2019. I also have separate versions for SQL Managed Instance and Azure SQL Database. My diagnostic queries have been used by many people around the world since 2009. I make regular improvements to these queries each month.
This is one of my favorite methods for learning about a new SQL Server instance.