cable knitting

[iamthemuffin.livejournal.com]

i'm attempting a cable pattern in my knitting for the first time. i looked up all the stitches, i understand what each symbol in the chart means....but i still can't get it to work! for example, the pattern and the chart both indicate that there should be twenty stitches across in the chart pattern, but if i count them, there's twenty-four. and throughout the chart there are black squares, and the directions say that when i reach a black square i'm just supposed to "ignore it". what the ba-hoo-ey?!

can anyone direct me to any tutorials that better explain this gibberish?