How to Make Crochet Fabric
To make a flat crocheted fabric worked in rows, you must begin with a starting chain. The length of the starting chain is the number of stitches needed for the first row of fabric plus the number of chains needed to get to the correct height of the first stitch used in the first row.
When working in rows, right-handers work from right to left and left-handers work from left to right, turning the work at the end of each row.
One or more chains are worked at the beginning of each row (or joined round) to bring the hook up to the height of the first stitch in the row. The number of chains used for turning (called a turning chain in patterns) will depend upon the height of the stitch they are to match.
single crochet = 1 chain
half double crochet = 2 chains
double crochet = 3 chains
treble crochet = 4 chains
When working half double crochet or other longer stitches, the turning chain usually counts as the first stitch (the project instructions will let you know if the turning chains are not considered a stitch). When one chain is worked at the beginning of a row starting with a single crochet stitch, it is usually for height only and is made in addition to the first stitch.
Below: LW4773 Cabled Hat with Pompom Free Crochet Pattern