Hide a Page from Nav Bar but available to those who know it

I am using an AWeber form, that once completed is brought to a Thank You Page. The Thank YOu Page works fine as long as I publish it as “Public” but I don’t want it to appear on the Nav Bar. Now do I hide this one page? I’ve tried to mark it as private – but then AWeber can’t find it (redirect)

Help please.

PS I”m not much of a techie – took me hours to figure out how to even get AWeber form to work in the first place.