Welcome to use my program, and help is available here!

Quickest way in my experience, for simple stuff, is write or type it in a text format, e.g. abc notation. It comes down to about 2 or 3 keystrokes per note on average.

The other quick way, if you have the expertise and equipment, is to play on a MIDI instrument into a file or program, but you will then probably need to quantize it.

There are just too many parameters for each note for a mouse to be efficient.

Once you get the basic tune in, the mouse is good for making changes though.