first locate and identify the expansion port..pin 1 is the top side far right as you look into the back of the expansion connector.
for reset you need a momentary push to make switch wired between pins 40 and 49 or 2, 49 and 2 are ground 40 is bus reset...
for a pause or freeze switch,you need a latching push to make or toggle switch wired to 39 and 49 or 2.
if your doing this internally try to use a point further back inside the machine on the motherboard so you can still use the expansion slot.
it would be easy to do with a multimeter to trace them back further into the machine...
if you get stuck ill post a picture of the expansion port pinout if you like.
basically you need two switches and three pieces of wire,and thats it.
important: bare in mind the pinout is alternating between the upper and lower pins as its read from right to left...so be careful mate
if this is incorrect in any way whatsoever someone please feel free to correct me