The end-user will see the Power Actions in a toolbar on the issue view.
The custom field shown above, actually defines 3 actions, but each has a different condition; Action 1 is enabled, Action 2 is disabled and Action 3 is hidden.
You can easily spot Actions that require a screen by the trailing "..." in the labels.
To execute an action, just click the respective button. If the action requires additional input from the user, a dialog similar to the one below will be shown before executing the Action Script.
Info
For more real life examples using Power Actions for JIRA(former Blitz Actions), please visit our Tutorials & Recipes page.