How to fit that plastic bit inside the LCD assembly?

Just bought a screen but it doesn’t come with the transparent plastic bit that fits underneath the notch.

There is a hook in that plastic part (circled in blue).

Also, the LCD assembly that I received has some kind of little plastic bit inside where the earpiece fits (circled in red). It prevents the earpiece (circled in green) from fitting into its normal place.

Is there a way I can fit this? Am I supposed to unglue the metal frame that is all around the screen assembly, for it to fit?

Will anything bad happen if I just cut off that little hook?