How to disconnect the largest wire plug on the amplifier

[goinstrong]

I have a "dumb" question: How do you get the big black wire plug disconnected from the amplifier? It shows how it should slide back, but I have been trying to push the tabs in that face the front of the car while pulling the plug backwards, since it looks like it should slide back and up/out. I am afraid of breaking the 2 front tabs, but it doesn't look like they are moving the nubs in to allow the plug to slide backwards. Unless my eyes are worse than I think, it doesn't look like I can pull the clips out to go over the nubs either. Help!
I am sure it is simple, but I can't figure it out. Thanks for any input/comments!
Tim

[Frankie]

I assume you are talking about the large speaker wire connector.

There is an outer sleeve that retains the inner plug and provides a cam on which the four nubs move. Insert a screwdriver in the small slot between the outer sleeve and inner plug (rear-facing side), then pry with the screwdriver. This action will begin to force the outer sleeve to move the inner plug along its cam, pulling the inner plug up and out.

[goinstrong]

Thank you Frankie! It has probably never been removed, so it was reluctant. I was able to get it off using your advice...