In days gone by it seemed that most patterns consisted just of row-by-row instructions that you followed along from top to bottom on the page as your knitting grew below your needles, usually from the bottom of a project up. Nowadays it is common for a chart to be included that helps the knitter visualize how the pattern will look when the work is completed. I normally use them for reference only, but some people find it easier to follow a chart when overwhelmed by the complexity of detail given in row-by-row directions. One the rare occasions that I've designed my own patterns, I've drawn them out on graph paper, making an easy-to-follow chart in the process.
When looking for a chart to include with this post, of course I couldn't find one that used an actual “x” for any of the stitches! Any symbol works to indicate a kind of stitch or knitting process; charts are filled with dashes and dots, circles and filled squares, arrows and other symbols, all of which are explained in the associated “key” somewhere on the pattern page.
There are a couple of rules to remember when following a chart in your knitting progress. One is that you are working from the bottom of the chart up, rather than reading from the top down. It's helpful to have the row numbers marked to the right of each row to help you follow along. In addition to that I've taken to putting a “<” or “>” symbol in front of the row, to remind me whether I'm working from right to left across the pattern (the “right side” of the project) or left to right (the “wrong side” of the work). I've learned the hard way that the finished product won't look anything like the design on the page if you're not careful to remember this important point. And even though the rows are numbered, it is sometimes easy to lose yourself in the mass of symbols on the page before you, so I place a ruler under the line I'm working on to help prevent mistakes, sliding it up a row at a time as I go along.
It's okay to lose yourself in your knitting; just don't do so on your chart!
“Your ears shall hear a word behind you, saying, 'This is the way, walk in it,' whenever you turn to the right hand or whenever you turn to the left.”