Long tail cast on with a thumb strand? Help!

Hello, I am working on a baby bootee pattern with two straps. I am to Row 25, or the right strap. But I dont get it! I understand how to do a long tail cast on but I dont understand how to do it with a thumb strand. Does anyone understand this? Please help! I’m so close! Thank you!

Sorry I am unable to post a link to the pattern. But its found on Saartjes Knits . com (no spaces) Do a search for Saartjes bootees.

A lot of people seem to have problems with this, and I made a video tutorial showing you how to do it, for this pattern

For the other strap, which might give you headaches as well, I also made a video.

I hope that helps.

You could do a cable cast on instead, but the video should help show how to do it with a LT.