To get to the alpha listing, one route is to click the "find person" box on the upper right while you are in a profile, and in the drop down menu you will see "list of all people" as an option.
One other thing - you mentioned having added a whole branch that needs to go, but you need to be very systematic about that or you will end up with small clumps of folks who aren't connected to anyone else still in the tree, and they can be hard to spot. To delete a large group, you need to start at the outer edges and work back to the point where if connects to the tree. For example, if the problem is that you incorrectly attached someone as the wife of your second great grandfather's brother, and then added her parents and grandparents, her siblings, their spouses, etc., you would start with her grandparents, then her siblings and their spouses and children, then her parents, and only then the incorrectly added "wife." If you start with her, you will for sure lose track of some of the relations, which is one way you can end up with "orphans" in your tree.
Good luck with this, and do ask questions if you get stuck on something.