Quote:Well, what happens is that I'll create a 'Background image' and duplicate it in 'Layer 1'. When I try to rotate the 'Layer 1' image, the background image changes as well.
Your screenshot shows an empty transparent layer and using the text tool.
To duplicate the layer use Layer -> Duplicate Layer
Then to rotate the active layer, (not easy to see active layer with that horrible black theme. Look for the white border) , use either the rotate tool and click in the canvas or Layer -> Transform -> Arbitrary rotation If you have a problem with the former. Both give the same little dialogue. When rotated click the Rotate button to apply.
..and a couple of hints...
Parts of the layer might be outside the bounds of the canvas, you can toggle view everything using View -> Show All
If you need to increase the canvas size to contain all layers use Image -> Fit Canvas to Layers
50 second animation demo of that: https://i.imgur.com/6YvDbyh.mp4