If you want to label each trace when it is plotted, use the ?exprList argument to the plot function to add a name for each trace. For example:
plot( v("/out") v("/in") ?exprList list("Output voltage" "Signal In"))
Plot is an ocean command and you can find more information by typing "ocnHelp 'plot" in the CIW, or referring to the SKILL Finder or documentation (SourceLink/CDSDoc/cdnshelp).
I hope that this is the sort of thing that you were looking for?