Install New Fill Valve and Adjust Height

What happens here

With the old valve removed, take the new Fluidmaster fill valve. The presenter advises adjusting its height before installation to match the desired water level, which should be roughly 3/4 inch below the top edge of the toilet tank or the fill line indicated inside the tank. To adjust, hold the black housing of the valve and use the gray collar to extend or retract the stem. The new fill valve is then inserted into the hole at the bottom of the toilet tank. From underneath the tank, slide the washer onto the threaded stem and then screw on the securing nut until it's hand-tight. Use Channellock pliers to give it a final slight tightening, being careful not to overtighten, which could crack the tank.

Goal: Securely install the new Fluidmaster fill valve and set its initial height.