Welcome to the community!
You may find the videos and resource links on the landing page of the Online Help for AutoCAD Architecture useful in getting started, particularly the links under the Learn heading. There are a number of free resources beyond the Online Help, such as YouTube videos and blog articles, but much of that will be focused on a specific topic, and not in providing a comprehensive introductory tutorial. If you have the budget, you may find something closer to what you want in a book or on-line video learning service.
There are a number of books on AutoCAD Architecture, but you will find that the current economics of book publishing does not allow for annual updates of titles for many programs, including AutoCAD Architecture. A Google or an amazon.com search should bring up a number of titles for you to consider. I am familiar with and can recommend the AutoCAD Architecture books written by Paul Aubin, having both used them myself and having helped update the most recent two editions, for the 2010 and 2011 releases. You should be able to use the 2011 book with the current release to get an understanding of the basics of the program; new features added since then would obviously not be covered, but there have not been any major changes to the way the program works since then. The book is written in the form of a tutorial, and you will work through the features of the program while developing two projects, one residential and one commercial.
I am not personally familiar with any of the paid video learning resources, so I cannot comment on the relative merits of any of them.
If you are serious about the program and want to get up to speed quickly, you may want to consider instructor-led classes that may be available in your area. Most resellers offer at least a basics course for AutoCAD Architecture, and there may be offering by other local educational venues (colleges and universities, community colleges, perhaps even adult education offered by school districts).
FULL DISCLOSURE: As noted, I assisted in the updating of the 2010 and 2011 editions. I was compensated for my time, but I do not receive any additional compensation based on book sales.
