On older bikes connector is big wide block just behind headstock, can be reached by removing right hand plastic cover.
New ignition has more compact connector, other half of new connector (bike/battery side) requires cutting off old wide connector & using bullit pushfits to each wire.
If you do not want to have different keys, you can drill out screws halfway down unit & just refit new lower half, which is switch, wiring & connector, reusing original key & steering lock.