SOUND MODULATION MATRIX window can be displayed by selecting "Modulation" on various QSEditPro Program Mode windows:
Main Editor window (right button of mouse click on SOUND panel):
In SOUND EDIT window (right button mouse click anywhere on Sound Edit window):
And bottom of SOUND EDIT window:
Changing SOURCE and DESTINATION in MODULATION MATRIX is done by clicking on corresponding labels and selecting from the Source/destination lists.
Status bar on the bottom of MATRIX window is interactive - it will display brief description of different sources and changes.
Did you ever wonder how it is done so for example amount of reverb applied to the sound can be changed using MIDI CONTROLLERS? In the case of GM00 AcGrandPno - it is set right here in modulation matrix: