how to use tool one piece locking gasket boler

[Trudy Mills]

I have the one picks locking gasket in place with window in it
How do I use the locking tool that comes with it

I have watched the trim-lock video
The guy does not show you how to insert the tool
I have tried many ways...poking holes in the gasket
I understand what needs to be done...
Thanks
My old gasket had an insert