The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Key Software Services, Inc.:
SmartWaiter is a supplementary app and works in conjunction with main application SmartMenu for iPad ONLY, available on the app store. This app is meant to receive push notifications, when food is ordered or food is ready in the kitchen and also when a waiter is called upon.