Putting Checker on Cache Page

Is there a video or instructions as to how to put a checker onto my cache page? These are my first challenge caches and the first time I am using checkers.

You have to place to html code in the listing which you find as follows

1. Open the link as provided
2. Click on in the "link" button on the right
3. Copy the code for the third option and paste it into your cache description
(You might need to first click on the green button above the description to put it in the right mode.)
4. Save & preview and submit for publication once you're happy with it.

After following the instructions above, I just get a copy of the link at the end of my cache description where I pasted it. I do not get the Project GC checker, but rather a Solution Checker that when hit says, "Correct! The coordinates for this cache have been updated."

What am I doing incorrectly?

If you don't see the usual challenge check icon you might need to click the Source button above the cache description box before you paste the code.

Also the Solution Checker can be swift of when you make the listing

What does "Also the Solution Checker can be swift of when you make the listing" mean?

Sorry I'm just struggling to understand this.

Sorry, auto correction problem with my mobile device

"swift of" should read "switched on or off"

("Also the Solution Checker can be switched on or off when you make the listing"