I am using starter button and not sure what kind of connection is preferred. Soldered joint or crimped connector? If crimped connector what kind? The book doesn't mention it.
just make your 2 pig tails as long as they need be to connect up and solder them on and cover with shrink wrap. hit um with the hair dryer. what I do is put something between the tangs like a piece of wood, or hardboard. clamp the switch down to the wood. strip off enough insulation so you can double over the wire. mate the wire up with the tang and clamp the wire down good so it rests solid against the tang and cant move. then you can go on and solder the joint. turn it over to solder the other side. slide the shrink wrap down and heat it.
...The holes are there so you can first ensure a good mechanical connection before soldering. Pass the wire through the hole and then wrap it around itself so it's hooked up...then solder and heatshrink.