If you are talking about the Basic Sock Chart pdf., it simply tells you the way to do a heel and toe for a certain number of stitches. You decide which number of stitches gives the right size sock that you want, and you go to that chart to find out how to work those stitches. So if the sock you want, with the way you are knitting it, is 68 stitches, you then go to the chart to find out how many rounds to work the heel over, how many stitches, etc.
You might do a child's sock on 68 stitches, or you might do a sock for HUGE feet on 24 stitches. Whatever, that's up to you, but once YOU have decided how many stitches will create a sock the size you want, you then use the chart instructions to determine how many rounds and stitches to work (for that particular stitch count).
And for shoe size, you work a sock to the right length for that foot, that information is not on the chart at all.