First of all, you need to know where to find the tool, look along the top of GIMP to the filter menu then go down to distorts and on the right the 6th link down is the warp tool. You cannot, however, warp without something there to start with. Therefore, build up layers of the colours and patterns you wish to use. The warp tools will appear in another window and I suggest you just have fun and experiment with the setting tab and deform mode tools.
Finally let your imagination take over. You can, however, over warp a picture so you need to control yourself.
Enjoy!
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