Indeed mouser is correct in that T-Clock never has, nor ever will require a key of any kind. So it should just run, assuming the right executeable is selected, and the default windows clock (which it hooks into) is visible.
Assuming you have a 64-bit copy of Windows installed, the 64-bit copy of T-Clock (Clock.exe in the x64 folder) should run ... Although the difference made when T-Clock first starts (with its defaults) may be a bit subtle. If you right click on the clock after running Clock.exe the T-Clock properties should be availables, and from there you can customize it as you like.
There is no install per se, just extract it to where you want it to run from, and then run it. I may do an installer in the future...but that will depend on whether or not Windows 8 kills it.