Set to pin, click the inside of the gear, and the inside of the c-channel circle. or flatstock in my case.
It should now align itself to the hole of you c-channel. Click the outside face of your channel.
Turn the camera and click the closer facing side of the gear (to your channel)
Once thats done, it should turn orange. Meaning its full complete.
(Make sure the C channel you are working with is also full complete(orange). If its your first piece, make it "default" where it says "Coincident"))
No problem when it comes to the questions, I can help you out to the best of my ability.