(3)-a. Setting Apex Class

Press the 'Setting' button to view a list of all available Apex classes in your Salesforce organization.



Select the class you would like to extend and click OK.
"Direct Editing on Studio" feature is not available for a Class that is already deployed.

　 　

Only active Apex classes (those that correspond with the selected screen based on the interface of Apex class) can be added.
For more details about Extending Apex classes, please refer to < 5-1. Apex Class Extension >.