porthole window replacement

[crieders]

I bought a few porthole replacement plastics but I could not figure out how to remove the locking piece at the bottom. I know I have read about this before and wonder if there are any good links. Thanks

[Ken Juul]

There is a small plastic plug in the center of the locking handles.  Pry it out with a small screwdriver or pointed knife for access to screws that hold it together.  Don't forget to replace the o rings.