Kean's blog, The Swamp and the AutoCAD Devblog have many posts related to this topic.
Searching through them will save you time.
Here is one such post where you can find related info :
Search the Autodesk Knowledge Network for more content.
New: Get an Activation Code
Mac OS X 10.12 Support
Windows 10 Support
Autodesk Online Store Help
Serial Numbers & Product Keys
Installation & Licensing
Online Activation & Registration
Network License Administration