well you see on the left side it has a list of scales. Choose a scale you want. Underneath the fretboard there is an orange square with a note in it. Click on the main part of the box and enter the root / key you want your scale to be.

Then you get a bit of entry on the fretboard. If this is still complex, click the yellow box above the window to choose scale. write 'No' instead of yes, to not display notes.

I find it easier to display the notes, as you have R (Root note, treat it as '1')... then you get 2, b3 etc.. to 7 to indicate a scale.

meh... dont feel like explaining more. Hell it aint rocket science!