How to tell guests about registry?

So my sister is throwing my bridal shower, but she doesn't have everyone's contact information. Our RSVP's were all online through Zola where there is a tab that clearly says "Registry" but so far no one has bought anything from it. The bridal shower is this Saturday, so either everyone is just giving cash (which I'm completely more than fine with lol) or they didn't notice the registry tab. Is there any way to let people know about the registry without being gross like "Hey pal don't forget about the registry which you can find at *website*" I'm just worried of getting a bunch of random stuff we don't need and not being able to return it.