The best way to learn a chart is to knit from one. I find they may following patterns so much easier. It did take me a while, though, before I could confidently make a chart from written directions.
On the majority of charts, the right side rows are read from right to left, and the wrong side from left to right. Some charts don't show the wrong side if you're just purling across or knitting the knits and purling the purls. All charts have a key to help you decipher the symbols. You read them from bottom up, each box representing a stitch.