It is really easy.
The CV Pad has 4 CV input. Let's connect some CV source for them.
In the example the first three CV input connected to the CV Shades outputs.(CV Shades, if no input connected, just works like a static CV value source, and the values can be set by the front panel knobs.)
The last CV Pad input is connected to the CV Pistons output.
(CV Pistons is a complex low frequency oscillator for producing interesting signals.)
But of course, the CV Pad inputs could be connected to any CV source.
The CV Pad has 4 CV output, and each of them are configurable on the front panel.
In our example, the first output connected to our instrument's CV input.
In the front panel click on the first CV output field and a menu appears. In this menu choose the "Quad fade by Control between CV in 1-4" or "Quad fade by Satellite between CV in 1-4" option.
And done... 🙂
Now we can fade between the four CV in value by mouse or by our fingers if we have a touch screen.
You can find a small example in the following file:
In the "CV Pad - quad fade example 01.cmb" example, the four corner is 0 (by CV Shades), 1  (by CV Shades), a slower LFO (by CV Pistons), and a faster LFO (by CV Pistons).
The instrument is the Europa, and the modulated parameter is the waveform of the first oscillator.
For the better understanding see the "CV Pad - quad fade example 01 w scope.cmb" patch. This is exactly same as the previous one, just a CV scope added for visualizing the CV values. Skope by Lectric Panda used here, but any other scope is fine.
The zip file also contains examples for controlling two external parameter of an instrument at same time
In the "CV Pad - double linear fade example 02.cmb" we can control the filter frequency of the Europa's filter on the X axis of the CV Pad, and the filter resonance on the Y axis. The 0 and 1 values provided by CV Shades for the edges of the CV Pad.
The "CV Pad - double linear fade example 03.cmb" is very similar. The differences are the CV sources, not just CV Shades, but CV Pistons used too.
So let's go, and make some tricky modulations for your favorite synth. 🙂