How to use Factory's matrix without a mouse?

[mungbeans]

I've just purchased Factory but am unable to create new entries in the matrix, the manual says to postition the mouse at a point of intersection in the matrix and move the mouse up/down while pressing the mous button.
However I'm using a laptop and not using a mouse, I can't find any combination of key and trackpad that has the same effect as usinga mouse button.

How can I add new connections in the mod matrix if not using a mouse?

[Sugar Bytes]

Hi mungbeans,

please let me know if you are on macOS or Windows.
Depending on your settings you normally just press your trackpad and scroll up and down using two fingers.

Best,
Nadine