Painting the POSKY 777

I am sure I may get blasted for asking this but I am fairly new to painting, have been painting the iFly 737 which has a left/right/belly part to the .psd file. With regards to the POSKY 777 I see the left side with all the different layer areas in the layers menu, as well as a section for the right side... But how do you paint the right side? All I can think of is after paiting the left you'd have to copy each layer from the left into the right side, but no clue how to get it to the right side....Any help is appreciated..Thank you.