Add a Multi Issue Operation

In the "Operations" dialog, click Add Operation in the "Multi Issue Operations" section. The "Add Operation" dialog is displayed.

Enter the following information:

• Enabled: You can choose to temporarily (or permanently) disable this operations.
• Name: Enter the name of the operation.

• Description: Enter a description for this operation.

  Only the operation name and description is displayed to the user. So both should be self-explaining.

• Executing User: Select this to execute the operation by a specific user. Select that user. If left empty, the user who triggers the operation will be used.
• Asynchronous Execution: Check the "Should this operation be executed asynchronously?" option to keep the user from waiting for the operation to finish. There will also be no positive or negativ feedback. 
• Additional Issues: Select User chooses if the user is allowed to select the additional issue.
  Select JQL Search to select additional issues by a JQL request. A text box "JQL Search" is displayed to enter a JQL command.
  
  Issue variables will be replaced.
  Select Field to select a custom field that contains the additional issues from the "Field" text box. For example, this can be a Issue Picker custom field provided by Teamworkx Issue Picker for Jira.
  

When done, click Save.
The new operation is listed in the "Multi Issue Operations" section.
Next, you have to add a step to the newly created operation.