my advice
Do check out the link for beginners in cardistry; it's really helpful.
I started with disc two of the Trilogy, and I do not recommend it. Though I've gotten along fine I'm sure the learning was a lot harder than it had to be and I'm constantly having to learn basic moves that are new to me. However, Flourishes 101 on disc 3 is a great resource for bigginers, though it's not comprehensive. Here are my suggestions:
1) Sure, check out YouTube. Learn some of the basic things like Sybil, the charlier cut, and the revolution cut. One reason I don't heartily recommend YouTube for all your flourishing needs is that you'll find that your style starts to look like everyone else's; it's hard to resist or even recognize. You have to get a variety of resources and do stuff on your own to get to know how you flourish. Just like magic, being able to execute a maneuver is very different from performing it well and originally.
2) Buy a basic resource of some kind and learn lots of the basic moves.
4) Start combining these moves or modifying them into your own stuff. The point isn't to make fantastically new flourishes (chances are you won't or can't), but by making new stuff you really learn and "own" the basic components. You also start to get an intuitive understanding of how packets of cards behave.
5) Once you have several/many of these under your belt and feel like attacking something a little more substantial, buy a higher level flourishing DVD or book like Daniel Madison's Dangerous or Dan and Dave Bucks' Trilogy disc 2.
One option is to buy the Trilogy, start with flourishes 101, then move on to disc two. Some of the easier cuts include Akria, Molecule Four, and a couple of the components of Jackson Five.