What's the use of these two things on the front fork of mountain bike?

From the direction we look at the picture, the left side is the locking adjustment, which can lock or unlock the front fork. On the right is damping adjustment, which can change the hardness of the front fork, but the effect is not obvious. In general, the locking knob is used frequently.

In the picture below, the blue on the left is the lock adjustment knob, which is marked with lock and unlock, indicating lock and unlock.

The black one on the right is damping adjustment.