Welcome to the forums!
I think one of the reasons you might be a little confused is that there seems to be different types of data in your screen shot.
The Conveyor number is probably an integer, the model is a string with both numbers and letters in it, lastly, the install date is probably also a string as it may have / or - in the date...... (Note, this is a guess on my behalf, please feel free to correct any assumptions on my side of things).
So, we have a button 'Enter unit info' and it needs to be just an integer, that is, which conveyor number you want the extra info for.
That button needs to be hooked to some code running in the PAC. The chart will be looping around looking at that number and filling out the string values that match that conveyor number.
Yeah, if the number is the same, the same string data gets added to the string variables, but that's not a big deal in my mind (OptoMary would probably add some code to check the conveyor number, and if its unchanged, skip the 'move string' instructions).
Does that make sense?
The chart is what moves the Model and install date into those strings when the conveyor number changes, not PAC Display.
Feel free to ask any questions or provide some extra info if I am off the mark.