The short answer is that you can do that. A few of my early mentors crushed grapes, dropped it in a barrel, and let it rock. No added yeast, nothing extra. While some folk wax on about how great their father's or grandfather's "natural" wine was, IME most of it was mediocre. Sometimes it was really good, and sometimes it was really bad.Just a silly question I'm new at this, why do you have to add all this Xtra stuff sorbets, clarifier? I thought you just add sugar and yeast ?
The guys that consistently made good wine put a bit more effort into it, and their results pushed me to do the same.
A while back I wrote a post on basic winemaking process, that is intended to provide a brief overview of winemaking, including defining terms and explaining what things did what. It will take 15-20 minutes to read. This doesn't cover all the details -- it's not intended to do so. But it provides sufficient information that more detailed descriptions will make sense without being overwhelming.