Many crochet patterns use a color chart rather than written instructions to show designs with color changes. A color chart is a grid, with each square representing 1 stitch.
Because most publications are in black and white, symbols in each square indicate the different colors. So, always refer to the chart key to find out which symbol stands for which color.
When reading a chart, you generally read the odd-numbered rows from right to left and the even-numbered rows from left to right, unless otherwise specified. You read the chart in this way simply because you work your first row after the foundation chain from right to left and the second row from left to right. Here's a swatch made from the color chart.