He'd mostly been exploring the cabin while Geralt had been out doing...whatever he was off doing. Jaskier had only paid a little attention at the others declaration earlier and had spent the rest of the time testing the beds nap ability, along with poking around.
Still, the question had him huffing a bit. "Of course I do. You shuffle them and they show you little pictures!" Ok so maybe he wasn't entirely up to speed on how they worked, but it couldn't be that difficult