Reply to Help Modding MF Classic

Hi guys i am new to the community , so hello everybody. I have finally decided to modify my MF Classic, but i do not simply want to add extra arcade buttons. I have recently disassembled all my gear that has stopped working, and now have a small selection of different buttons i would like to add to my MF. The problem is i am little unsure on how to connect them to the expansion port. Do i simply need to attach one leg to the numbered ports and then one to the ground, and also what do i do when it is a three legged/wired button? I have attached pics so, hopefully one of you will be able to help me.