Reply to got an old gamepad controller, what to do?!

hey guys..

i got an old speed link game pad from a friend of mine. i opened it and am pretty eager to do some kind of midifighter with it.

the thing is, i don't know where to start.
how can i solder for example arcade buttons to the button connections (see picture, the buttons just press some kind of plastic on the pcb to connect.

do i need this big chunky metal parts, which are connected with black/red wires, they don't send any signals (in junxion) and are for weight issues, i suppose.

is there any possibility to implement pots? the thing has 17 buttons and the 2 playstation thumbsticks

thanks very much in advance..
wp