I am a newbie and I don't have enough reputation to add a comment on any previous questions. I'm currently stuck trying to make the bottle thread.
Here is my current situation :
I tried to do the way that @Xtremity gave on the first video from this question : How to model the bottle threads?
and then, when I try to select the faces that I want and invert it, it also selected the rest of the bottle. So, what should I do from here and how ?