2000 Chevy Blazer

How do I replace the heater core i have the dash out but can't seem to get the cover off to access the core itself is there some special thing that I must do or what

How do I replace the heater core i have the dash out but can't seem to get the cover off to access the core itself is there some special thing that I must do or what


Here is a link to the how to http://www.automotiveforums.com/vbulletin/showthread.php?t=368427