Need help understanding PAD Diagram

I just purchased this pad to use in an arcade stick, but im having troubles understanding the diagram.

Is it a common ground pad?

Do I need to have 1 ground for the d-pad and one seperate ground for the buttons?

If it is a common ground pad, all the things marked as common, do I just use any one of my choice for the ground? Or am i not reading it correctly.

Heres the pad

That thurr is not considered a common ground pad, you can see all the different colors shown for the various grounds, any circled that are of the same color are common to eachother.

For example, Back(BA), Right(RI) and LeftClick(LC) are all cyan in color and are all common. They can be wired together to the same ground, but they must be seperate from the rest of other grounds.