WHAT DOES THIS CROCHETING PATTERN MEAN?

The chain 1 is a turning chain and the 200 stitches is just letting you know how many stitches there are across that way you can have an accurate number of stitches which might make a differences in some patterns. When I began to crochet I counted to make sure I had the right number of stitches. When I didn't I somehow left out or added stitches so my afghans were different lengths on both sides. I don't have to count as much now that I'm a little better but those numbers were a great help.