If you didnt use the water editor before, starting with the default will be easiest. I dont think there is a difference in the water editor in v7.5 PLE, but I never used it so I maybe wrong. Just try it, you can always post more questioned if you encounter problems:)

"I paint that which comes from the imagination or from dreams, or from an unconscious drive. I photograph the things that I do not wish to paint, the things which already have an existence."
Man Ray, modernist painter
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