If you're not a self-learner, you should:
1) Forget everything you know about AutoCAD; welcome to the world of not drafting
2) Seek out an Authorized Training Center in your area or online as mentioned
If you are a self-learner:
1) Forget everything you know about AutoCAD; welcome to the world of not drafting
2) Review the wealth of resources online as mentioned above (YouTube, CAD Learning)
3) Assemble a CD set of your home or another place that you know very well
In any event, if you're seriously devoted to learn, just do it, kick out the crutches and prepare yourself to the world of virtual construction. Yes, there will be some drafting and likely 2D sheets, but that's not the focus anymore. The less you try to make it work as AutoCAD did, the better off you'll be and the sooner you'll grasp the core workflows.
After you're comfortable with the basics, seek out knowledge on things like Level of Development (LOD), lifecycle data, and the like. Don't let anyone tell you that you need to prepare and model everything, or answer any technical questions about the design you're not ready to on the first day. As with design, it's a progressive, iterative process, and a decent project template and library go a long way to helping you augment your design as it evolves and matures.
Finally, ask ask ask... as you're apparently already discovered. I like to think we're a good community, and while we may occasionally disagree, eventually we're all here to help.
Aaron Wagner | Technology Consultant – Autodesk Construction Business Line Lead
U.S. CAD | Achieve More
Rocky Mountain Region, Denver, CO
T: 877-648-7223 x301