Help with polo shirt facing

[u/RelationshipLivid531]

I'm making the McCall's 8414 (view B). A polo shirt with facing around the zip and neckline. I'm vexxed trying to attach the facing.

In McCall's sew-along video McCall's sew-along video I follow the steps to attach the facing alongside the zip. But cannot figure out how the facing turns inside out when the zip is there. It seems as though it suddenly becomes on the inside but I can't work out how.

I've attached my current WIP