Uh.... He programmed it?
Uh... Extract then open(double-click) the executable.
You can. When the launcher opens, select the Input tab.
Watch iwan's video.
Check your keybindings.
Extract the file, then go into the folder that is created. Double-click ravenfield.exe. If that doesn't work, you'll have to explain more.
What? The game is already offline.