I bought the FJG S2, but it says it comes with ARN, although the name of it installed is FJG S2 20, which would suggest that it doesn't, and when I checked, it can only be No. 20. I also bought the PRR RS1, how do I open the hood and cab doors, move the sunshades and shutters, and move the truck chains if they are interactive?
I don't know about the S2, though probably uses ARN just for that number(similar to their NS 8099 and 8098)

For the RS1, you right click (windows/mac desktop w/o Magic Trackpad), or Control-Click (mac) and you get a big list for all of those features.
That unit does not have ARN, and should not be labeled as such. Sorry for any confusion. To use the animations (on both units), ctrl+click and you will see sliders for the different options.