The timer was never actually implemented in the template, because there was no interest in it, while other features were kept being requested. I’ll put it back into my todo list now.
It probably won’t be the same design as the one in your screen recording though, because I couldn’t come up with a way to generalize it on multiple-choice cards. The second style from the demo seems more practical to me at this point:
While it’s not as unintrusive, in my opinion, it still beats the original Memrise design, which required constantly flicking eyes to the very corner of the screen and back to keep track of the time while typing.
If you’re up for it, there is also a prototype code, distilled from my other card template, which you can use to set up the timer. If you tell, what kind of behavior you expect, I’ll be able to provide more detailed instructions.