What is the dough and where do you get the dough that they use in all the food tutorials?

Dough is made of flour, salt, and water. Everything else that might be added is either a flavor or a dough conditioner. Yeast is naturally present with wheat, and some bread, called sourdough, is raised from that natural yeast. Most people use store bought yeast because it acts so much faster. Citric acid, ginger, and sometimes sugar are added to promote yeast growth. Lecithin is added to help the bread stay fresh longer. Oil and egg white help keeping properties and also affect the texture and color of the bread. Egg yolk might be added for flavor. Gluten is an important part of the raising, so extra gluten is sometimes added. A baker can make a dough about as easily as a dancer can do a pirouette.

You say "all the food tutorials" and my answer only applies to breads. So maybe I don't know what you are talking about.