This article covers setting up and configuring Azure Active Directory Domain Services (DCaaS). The article includes a video demo going over the 5 task needed to setup and configure Azure Active Directory Domain Services (DCaaS) correctly.
Video:
Steps in the above video covers;
Create administrative group
Create or select a virtual network
Enable Azure Active Directory Domain Services (DCaaS)
Update DNS settings
Deploy and join Virtual Machine to Azure Active Directory Domain Services (DCaaS)
Login to Virtual Machine using Azure Active Directory users
Microsoft Azure article covering some of the steps in video