Truck scales come in 2x2 types
ONE split: Bridge or flat (Flat is needed for proper weighting of RV's but if all you want is total weight, Either will work,, There is another advantage to flat though.
Other split, Segmented/not segmented.. If all you want is total weight does not matter.
Pull onto the scale, if it is segmented make sure each axle is on one segment only and only one axle per segment. NOTE Bridge scales you need to be very careful pulling on to them as the rails are just wide enough to pass your wheels and the front simulators can get tore up some if you hit the rail.
Flat scales do not have that problem.
Contact weight desk (usually a phone provided) and they print a card (or follow instructions on sign)
If segmented then total weight is sum of segments.
For proper weighing of an RV, you need a flat segmented scale.
Do as above (Without worry about the rails and your simulators)
Then pull on again so that only one side of the RV is on the scale and the other is on the ground
Get and pay for both cards.
Total weight is thus the weight of the RV off the first card, add segments as above
4-corner weight The side weighed in the 2nd pass is easy it is no the ticket
Subtract the side weight from axle weight for the other side.
Now you can go to the tire makers web site, Download the inflation chart, and figure the proper PSI for each wheel, Most folks like to add 5 PSI to the chart. NOTE that each wheel may be different than the others.