Woogeroo,
A little web searching turned up the below picture which should help with the details on how to install your repro switch.
These repro's are used in the majority of GM products of the mid '60s vintage and the kit contains a "lamp holder" (copper bit) that probably wouldn't have been original to your C10.
The pic does kind of give you an idea of the assembly sequence so you can get it into your dash. Just need to top it off on the outer side of the dash with your original "bezel ring".
Hope this is helpful?
Dan
