GIMP Help Needed

i was following the tutorial on modeling a low poly camaro by karan shah found at i did all the modeling and UV unwrapping steps correctly and i can not get the final steps done in gimp,as i don’t have much knowledge of gimp so i would be thankful if anyone could help.In particular i am having following problems (see the picture below)

  1. How do i add shadows and highlights? (marked in black)
  2. How am i suppose to crop windows and lights pictures and paste them on uv map layer (marked in red)

Plz tell me everything i need to know, you can also suggest any tutorial


To start with, find a few tutorials on using layers in Gimp. You can put the UV layout on the top layer, but add additional layers for the different parts (or colours) of your car. E.g. have a layer for each window, another for the shadows, another for the wheels etc. Mask off areas of the car and use the blend tool for the shadows. With each window on a different layer (with transparency), you can scale and move the windows where you want them. You might also want to use the path tool so that you can save outlines and masks in your image - find a tutorial on this, because the path tool really didn’t work like I would have expected it. Save your file in gimp format (XCF), then turn off the UV layer and export the other layers to a JPG or PNG.