When crocheting, you will almost always need turning chains. Both when starting your work, and also along the way, when you need to turn your work after each row. Turning chains consist of chain stitches, the purpose of which is to get the crochet hook to the correct height for the stitch being used. The number of turning chains will therefore vary depending on the type of stitch you are working with. The number of turning chains can also vary depending on how tightly you crochet. If you crochet very tightly, you may need an extra chain stitch to get the crochet hook to the correct height, while you may need to make one less chain stitch if you crochet very loosely. 

Turning the work when crocheting with double crochet stitches

1. Make 2 chain stitches and turn the work
2. Make your first double crochet stitch in the third stitch from the hook