I needed to replace the ingition in my 1968 , so I purchased the switch and the lock but cannot figure out how the lock goes into the switch? is there a secret? or am I stupid? 

You're not stupid, it's just a little tricky. Look at the face of the lock, you'll see a small hole. Insert a straightened paper clip into the hole and push on it just a bit. The lock should then twist and slide right in.

I believe you have to have the key inserted also.

Dave, The hole is a thru hole? so how can I push on it?

Hold up Hold up, I found the answer, my buddys at Ecklers sent me the wrong lock. I thought I was going insane.

Sorry for the run around