Here you can see the anatomy of a chain from the “front” side. The stitches look like little “V’s” and they have a front and back loop. If you are working on a design that will need you to work both sides of the chain, start by working your first stitches under the front loop only. 
When you finish the first portion of your row, it should look like this. You will now flip your work over and use the unworked loops on the other side to finish the row.
In this photo I have completed a stitch already on the back side of the chain and have inserted my hook for the next stitch.
Here is the finished row.





