ScooterHelp has a good set of instructions for this.
Basically, the knob end has a double-90 degree bend, and I'm not sure what the T5 has on the carb end.
The double bend passes through the hole in the knob shaft. There's only one correct direction, so be careful.
The other end connects to the choke part of the carb.
The hairpin spring clicks against the choke knob in a way that is as simple as it is indescribable, and provides friction to keep the knob where you put it.
You disconnect the carb end and pull the knob all the way out of the tube, then disconnect the wire, pull it back out, push in the new wire, slip it through the knob shaft the way the old one was, push the inner back through the outer, and reconnect to the carb. Check and photograph the position of the hairpin spring first, because you'll never remember it afterwards.
But look at scooterhelp - it describes it well.
- Eric