Long tail cast on ?!?! please help quick!

I am sooo confused! How do I do the long tail cast in the middle of a project?
I am doing Saartjes Bootees (cant post the link, since its a PDF, but it can be googled)
and I just BO and not I am supposed to CO using long tail method, but how do I do it with just one strand?

Its says "cast on using long tail cast on and second strand as the thumb strand"
but there is no second strand? I am SOOOO confused!!

I am making the booties for a baby shower for tomorrow and i need to finish them ASAP!

You can use the backward loop method, the knitting-on method, or a cable cast on. Both of which are shown in Amy’s Basic Techniques: Cast-On. HTH and good luck.

PS. Check out this thread also if you have the chance:

You are supposed to use a second strand- like a scrap of that yarn. Cut it from the opposite end of your yarn ball.

You don’t always need to do a longtail CO when you’re in the middle of something. A knitted, cable or backwards loop CO works fine and videos of them can be found in the Basic Techniques section above.