Salut,
I was trying to figure out how to use this tool, and I had already watched some videos about how to use it, at least a 3 or 4.
This time I finally understood that.
Even using a different version (2.10 here), I was able to follow the tutorial in PDF without any difficulty.
Many thanks, Issabella for helping out a noob like me learning to use Gimp. Thxs.

Btw, my thanks also for Jec112203 for the video, and for Doronf2 by video and picture! Thx guys!

You should post your reply in the appropriate topic where it was discussed, instead of creating a new one.
It's hard to say what you are referring to, and makes no sense anyway.
But I guess it was the foreground extraction:

viewtopic.php?f=10&t=16439

Sorry, that was my intention, but I do not know what happened.
Could any moderator move this post to viewtopic.php?f=10&t=16439.
Thank you.