The green lever of the throttle knob did not leak out.

First, you have to determine the opening direction of the valve. Generally speaking, closing the valve is the right direction, and opening the valve is the opposite direction.

The use steps are as follows:

First, make sure to open the valve, usually a ball valve, and turn it 90 degrees.

Second, there is a button at the top of your pipe that can be pulled. It varies from place to place, some are pulled in half, and some are all pulled up.

Third, there is something similar to a black disk below, commonly known as the empty nucleus. This is the same as the second one. Pull out half or all, and you can use gas.

The green button is called "explosion-proof valve". The stainless steel in front of the button will only flow out when pressed. The green one at the back can be rotated to adjust the air pressure.