How to Loop cast on?

I’ve started my first “real” project the Ottobre soaker pattern. In the increasing section of the pattern it tells me cast on 3 stitches to both edges of the work using a loop cast on. What in the world is this? is there a video to demonstration this here?

Warmly,
N

Yes, it’s the backwards loop or Single CO on the cast on videos page.

Thank you!