Use the macOS User Guide
The macOS User Guide has a lot more information about how to use your Mac Pro.
Get help. Click the Finder icon 
in the Dock, then click the Help menu in the menu bar and choose macOS Help to open the macOS User Guide. Or type a question or term in the search field, then choose a topic from the results list.
Explore topics. To find a topic in the macOS User Guide, you can browse or search. To browse, click “Table of Contents” to see the list of topics, then click a topic to read it. Or type what you want to find in the search field to go right to your answer.
Find out what’s new. Click the Help menu, then choose “See What’s New in macOS” to find out more about the latest features of macOS.
Tip: If you can’t remember the location of a menu item in an app, search for it in Help. Place the pointer over the result, and an arrow shows you the command.
Learn more. See the macOS User Guide.