Holst a test valve and fix to the place, near its right flange end to the blind of right work bench, adjust right jaw to advisable position, press the button of "right jaw clamp" for gripping the right flange of tested valve. press the button of "frame onward", make the blind of left bench compacting left flange of valve, adjust left jaw to advisable position, press the button of "left jaw clamp" for gripping the left flange of valve.