@Winny1 You'll need to create your own Netflix account first. Once you've signed in with that account, Sky will take over the billing with your Sky Stream subscription.
Follow the section named If you don't have an existing Netflix account: on the following help page: https://www.sky.com/help/articles/apps-on-sky-q-and-glass-using-netflix
Sky Glass & Stream Puck customer w/Sky Entertainments & Netflix, Sky Cinema, Whole Home & UHD/Dolby Atmos add-on.
