You can weigh twice on a CAT scale and the second weigh is discounted. To get the key numbers you need to weigh twice. Once truck only, once hitched up. You will get weights for steer, drive and trailer as well as the gross.
The speakers on those scales are designed by the same people who design subway speakers and they are nearly unintelligible. It helps a lot to know what questions they may ask...
If they are busy you may get a "wait one minute please", or maybe the first question will be "first or second weigh", the next question is usually "truck number" (you can say "private"), after that they say "pull forward". You go in and pay and get the slip.
Your pin is the difference between the two drive axle weights. Your gross is the gross (hitched up). Remember that tools, fuel and passengers can matter.