The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
As Kelvin, you've become the farmer on a futuristic farm. The chickens and cows need your help. They won't produce eggs and milk on their own - they need you to feed and water them, and clean up their stalls. Once you have your eggs and milk, you teleport into production where it's your job to wash the eggs and pasteurize the milk. Can you keep the animals happy and get all the eggs and milk out to market?