Good Knight!

The thing with the movement of the knight is that it always lands on the opposite color, so if you place all the knights on the same color none will attack each other. You can put $32$ knights and none will be able to attack another one in one move.

We can see that, we aren't able to place at least one more knight in this chessboard(so that they can't attack each other in one move).

Therefore $\color{#3D99F6} \boxed{32 ~ \text{knights}}$ is maximum.

If you put them all on the same colored square you can do it with 32

Just put all on white square. It was my problem. I posted it a long time ago