where can I find my taskbar on my desktop Mac?

On a Mac it is the Dock at the bottom of your screen.

Use the Dock on Mac - Apple Support

You also may find https://support.apple.com/explore/new-to-mac useful , it sounds like you are new to Mac OS. There are LOTS of resources available to you to make the transition easy.

A taskbar is windows terminology, and you are on a Mac, so the Dock is the analogy, and it is located at the bottom of your screen.