Ancestry.com is a website and provides online Member Trees.
Family Tree Maker is a stand alone genealogy program that runs on a computer that is owned by Ancestry and syncs with Member Trees on Ancestry.com
Ancestry Family Tree is an older software program Ancestry used to provide but no longer sells or distributes. It was replaced by Family Tree maker.
As to looking at/copying from other family trees... DON'T!
Do your own research from scratch- that is the only way you can be sure it is as correct as you can make it.
Looking at family trees is *NOT* doing genealogical research.