Removing Vignetting With GIMP

Does anyone have any tutorials for techniques to remove vignetting (i.e. light fall-off due to a wide angle on a FF camera) using GIMP?

I don't know if I'm misspelling something because my searches haven't really turned up anything that I've managed to get to work yet. As beginner friendly as possible would be great; I'm very much new to post-processing in general.

Really wishing I had Photoshop for this one, what with the automatic tool.

Thanks
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