How do I use Phos Flur mouthwash?!?

I'm confused, it says do not eat or drink anything for 30 minutes, does that mean I swish with the phos flur and do not rinse my mouth for 30 minutes or swish with phos flur, rinse then do not eat or drink for 30 minutes? So my question is do I rinse or leave it in my mouth for 30 minutes?