New Front Carpet Heel Pad Location

I was wondering if anyone could show me a picture or explain about where the heel pad should be during the time of replacing the front carpet. I have pushed the carpet up as far as it will go and it still seems like the heel pad is still not far enough up, I know I can trim the top which will allow the carpet to be forced higher up but just would like to see pictures of your location.
Please help.
1972 Plymouth Duster