Open the template into GIMP, after you have downloaded and installed GIMP. Then, just play around with the colors. You will have to get a feel for learning to work with the layers, like editing the tape colors, the spoiler and splitter colors. For now, I suggest you just play around with gradients and try making your own bases on the painting layer (the absolute bottom layer). Good luck, and if you have any questions, feel free to ask. I am not the best of painters, but I know a bit about it.