Almost all crochet begins with a base foundation chain, which is a series of chain stitches beginning with a slip knot.
How to make the beginning loop (slip knot) and chain stitch
video includes link for left handed tutorial
(1) Make a circle with yearn or thread.
(2,3) Pull a loop through the circle.
(4) Insert the hook in the loop.
(5) Pull gently and evenly to close the loop and slide the knot up to the hook.
Wrap the yarn from back to front over the hook (or hold the yarn still and maneuver the hook). This movement of the yarn over the hook is used over and over again in crochet and is usually called "yarn over", abbreviated as "yo".
Foundation Chain: (Chain stitch)
Yarn over and pull the yarn through the loop already on the hook to form a new loop. Be careful not to tighten the previous loop.
Repeat to form the number of chains specified in the instructions. Do not count the slip knot as a stitch.
Working into the foundation chain:
When working into the starting chain, you may work under one or two strands of chain loops as shown in the illustration. Either of these methods forms an even, firm bottom edge.
Some people like to work into the "bump" on the back of the chain. This forms an even, stretchy bottom edge that is ideal for garments.
Whichever method of working into the foundation you choose, be consistent. Work all the pieces of a project in the same manner.