How to do a foundation Slip Stitch?

[Maddy429]

I've been stuck on this pattern for a while now. Wondering if I could get some help on how to correctly do a foundation slip stitch, thanks!

[Granny Square]

Welcome to the 'ville!  I've been crocheting for decades and that is a new one on me!  I'm not a fan of foundation stitches to start a project (because it is not always appropriate, I don't thing the appearance is better than starting with a chain, and it does not  work for some lace patterns for example); I only resort to it for widening the shape of existing fabric.

A slip stitch is never used as a foundation (rather is more of a height-less 'scoot over' existing stitches), so I'm curious how it's used.

Here is a video that is making a cord, (OK, a cord makes sense) - does this help?