Reply to Add arcade buttons to a VCI-100

Hi all !
I would like to add arcade buttons to my VCI-100 but I don't find any electrical scheme on the site.
Why does we need " 8 Diodes 50 PRV 200ma switching diodes " ? Where input them ?
Maybe a thread have been ever made but I don't find anything...

Thx for your answers !

Cya all