Read this:- Run Modes
//There are two pairs of mutually exclusive run modes; for example, you can:
So default when you open AEM instance by double-clicking, it will open author + samplecontent Which is used by devs.
There is one more concept here to open AEM instance in Debug mode: java -jar cq-quickstart-6.0.0.jar -debug 10123
Read more here:- How to Develop AEM Projects using IntelliJ IDEA
Refer below links which helps you to get started and setup the development environment -
For developing on AEM it is quite common to use an instance installed on your local machine running Apple OS X or desktop versions of Microsoft Windows or Linux. For more information, refer: Technical Requirements
Customers with a valid maintenance and support contract should have received a mail notification with a code and be able to download AEM from the Adobe Licensing Website. Business partners can request download access from email@example.com. For additional information see Download AEM.
The AEM software package is available in two foms:
cq-quickstart-6.3.0.jar: A standalone executable jar file that includes everything needed to get up and running.
cq-quickstart-6.3.0.war: A war file for deployment in a third-party application server. For details on installing AEM in an application server see Application Server Install.
Note: Generally, when you set up Adobe Experience Manager (AEM), you need to set up an Author and a Publish instances.
Installation procedures for these are described in Installing an Author instance and Installing an Publish instance.
We hope this information helps!