I watched the cast on video and did that. I now have a long tail hanging off my the little row and I am not sure where that is supposed to be once I start the knit stitch. The video for the knit stitch shows it after several rows have already been done so I was not sure what to do with mine. I also have a stitch n bitch book which did not mention what to do with the litte tail (not the one attached to the ball of yarn).
You can cut it to about 6 inches or so and then weave it in when you’re done. 
I use the tab from a bread bag as a bobbin and wind up the long tail until it’s about 2" from the end of the row. Then just let it dangle. After I finish my project I use the long tail to sew up the seam or use a crochet hook to weave it in. Welcome Aboard.
It can be ignored for now. You may want to cut it shorter if it is any more than 5 inches so that it is out of the way.
Once you have done your knitting the loose tail can be woven into your kniting to hide it or, in some circumstances it can be used for seeming a piece or sewing up an item.