Michael, you need an early ('65-'73) 911 (or original 914/6) turnsignal-cancelling ring - it looks like the one shown in your photo is for a 914/4 (smaller overall diameter).
This is the one you want:
You also need the spring & 'cup' washer :
& the spring-loaded horn contact:
Once you have all these parts, this is what you need to do:
Place the (911) cancelling ring on the back of the steering wheel by lining up the holes where the horn contact fits - red arrow in picture below:
Next mark (on the back of the wheel) the position of the mounting holes indicated by the yellow arrows.
Remove the cancelling ring & centre puch/drill/tap (M4) 2 holes where marked.
Countersink these two holes - the back of your wheel should now look like this (green arrows):
Now you can fit the cancelling ring using 2 short M4 csk machine screws, horn contact, spring & 'cup' washer (making sure it's orientated like in the earlier picture).
Fit the wheel to the splined column (making sure that the road wheels are pointing straight ahead), add the washer & nut & tighten down.
Hope this helps.