Learn more about activating your subscription plan and to assign licenses to use tools like ArcGIS Pro or AppStudio Developer Edition among others. This video will walk you through:
Access to my.esri.com 
Introduce Developer Subscription Code 
Access to the developer subscription status 
Active ArcGIS Online Development and Testing Organization 
Set up your ArcGIS Online Organization
Assign ArcGIS Pro, AppStudio Developer Edition, and more licenses
Learn more about building, testing, and deploying ArcGIS maps and apps  at https://developers.arcgis.com/