It means that instead of crocheting in the back loops, you crochet in the sides of the previous however many rows you've already made, so the pattern goes sideways.

This YouTube video may help you understand.

crochet along edge

donna_loomis, The video was just pictures of completed projects and music. It wasn't a tutorial.

Were you referring to the one titled "How to Crochet a Border"?

I'll take a look at it. Thanks for replying!

When you work on the sides, that means that you are going up the side of the work. Probably you are crocheting around something. My favorite baby blanket has you go up the sides of the blanket to give it a nice edging when you are finished with the center of the blanket.