Does AutoCAD Architecture appear in http://manage.autodesk.com/?
If not;
If you're a student you need to request it: https://www.autodesk.com/education/free-software/autocad-architecture
If you manage your own licenses you should contact support: https://knowledge.autodesk.com/contact-support/installation-activation
If your licenses are managed by you employer then speak to your contract manager.
After you click Run ... are you able to use your Sign In to activate it?