Both have tutorials. Ancesty.com, at least (and probably genealogy.com) will let you build a family tree on-line, with no program needed.
BUT 1) A decent genealogy program (Roots Magic is my choice, but there are others) is only $29.
2) If you have your data on your PC, you can abck it up as often as you like, to a thumb drive or CD or cloud server.
3) A program has a lot more features than the ancestry.com family tree on the web.
4) It would still be yours even if your subscription to either lapsed.
5) If it isn't on the web it can't be hacked.
Having a genealogy program isn't all sweetness and light. One major disadvantage of having it on your PC is that your brothers would have to send you data.
A second is that, fate being what it is, the day your hard drive crashes will be the day after you entered 12 hours worth of data and forgot to back the database up. Both on-line services are as crash proof as you will get.