2002 tahoe dynamat

[bassHZ]

got rattling coming from the rear side pillars on the outside of the truck the ones right next to the window hatch ..i bought some dynamat layed some on the inside but the rattle is still there now i wanna lay some on the outside how do u remove the panel i removed the top screw but there are some clips on the inside what tools do you use to remove that cuz i used a flat head and it seams like its gonna break ??