The symbols on some charts differ, but there's always a key for the symbols.
Charts are read from right to left, one stitch per box, on the right side.
The wrong side rows are ready left to right. Sometimes, if the wrong side is just purled, they don't even include it in the chart.
One thing to remember with charts is that what appears in the boxes is the result of the stitch. So if you work a decrease of two stitches down to one, there will be a decrease symbol in one box, even though you're using two stitches. If there's a yo, then the 0 in the box represents the yo after it's done.
I love charts and think they make knitting much easier. It's important, though, not to overthink them. Just do whatever is in each box or group of boxes (for cables) blindly, and you should be fine.