How to volume: First you must click on the red-boxed button to bring up the note settings window.
Clicking said button will bring up the note settings window, which looks like this:
Volume, boxed in blue, is set at a default of 100%. By sliding the little arrow/triangle thing below the 100% bubble to the left, you decrease the volume of any notes you place after you close this window. The furtherest left value is 0%, which will make all notes inaudible.
Inversely, sliding the arrow to the right increases the volume of any notes you place after you close this window. The furtherest right value is 300%, which will make all notes much louder (3x louder to be precise) than the default 100%.
Panning, boxed in green, controls from which speaker a note plays. As far as I know, this will have no effect on systems using sub-stereo systems. The default of panning is 0%, which means a note will play with equal volume from each speaker. By sliding the little arrow below the 0% bubble to the left, you increase the volume in your left speaker, while decreasing the volume in your right speaker. The maximum left-bound value is -100%, which means that sound will come from the left speaker only.
By sliding the little arrow below the 0% bubble to the right, you decrease the volume in your left speaker, while increasing the volume in your right speaker. The maximum left-bound value is 100%, which means that sound will come from the right speaker only.
Note Duration, boxed in yellow and red, controls how long a note is sustained. The lower the value in the red box, the shorter the note. By clicking on the yellow box, you will bring up a list of some preset note lengths. The default quarter note has a value of 16. Each measure has a total value of 64 units, which means that when evenly spaced, one measure will accommodate 4 quarter notes. You can set a note to any value between 0-1000 by typing the desired note length in the red box. The maximum value of 999 will hold for about 15⅔ measures.
When you have set all of these factors to your liking, click the "change" box at the bottom of the window to confirm your changes.