Hey! First of all, thank you so much for playing the game!
And sure! There is a diary on the guard's table that serves like a hint but the thing is, the amount of knocks is equivalent to the number of the first digit, then after a clap, you count again the amount of knocks and that's the second digit, if there is just two claps and no knocks, that mean just zero.
So that way we have:
2 knocks
0 knocks
4 knocks
8 knocks
6 knocks
3 knocks
And after that, it just resets again because those knocks are actually the current password :) twozerofoureightsixthree.