Can someone guide me to some instruction about hydration? Never heard of it before.
To add a bit to what Dan said (love your book, Dan) -- and maybe you don't need this, Vonilda -- you may see terms on TFL like high hydration or low hydration. There's no defined point where that breaks (as far as I know!), but as general terms they are descriptive. High hydration doughs -- those with a high percentage of water in relation to flour -- will result in very different loaves when compared with loaves with low hydration. For instance, if you're making a French baguette you're aiming at a much higher hydration level than if you are making bagels.
Also generally speaking, doughs with different hydrations will require different techniques in the making.
The "breaking point," in my experience, is any dough that has you praying the phone doesn't ring while you have your hands in it ;-)