Ardour is designed to work best with a three button mouse equipped with a scroll wheel.

It can be used with a two button mouse or touchpad, but at least two key operations will not (easily) be available to you:

You are strongly encouraged to invest in a three-button mouse. You will find that a good quality mouse (especially one with a weighted, latchable scroll wheel) will make your use of Ardour vastly more efficient. They are cheap, and time is not.

For more detailed instructions, see Using the mouse.