Sky offers 3 parts: sky Sport, sky Show and sky Store. These can be subscribed individually, and new options may be added by sky. The easiest way to find out what what is offered here. below and you can then review all the details and the current prices at sky.
To enjoy sky you need a subscription from sky Switzerland, to which you can first subscribe separately on your computer or tablet. Then you only need to log in to sky once on the TV box and you will stay logged in.
By the way: If you see a message "update required", you can ignore it and continue watching without any problems.