To make one side different to the other, you need to make two body textures.
Call one BodyL and one BodyR. I put my presets in png format, but jpg works too.
As posted above, there are places to put the names of the textures for the left and right side of the body.
Put the BodyR texture into Preset_1_BodyR place, and opposite for the BodyL.
Make sure your textures are jpg or change the .jpg to the right format, common mistake I make xD