Informant is a very flexible and powerful application. It has many features to help you mange your events and tasks.
One of those tools are the next actions in the tasks.
The next Actions work best with the GTD or Standard task mode enabled in Informant.
A next action is label that you can apply to your tasks inside of a project. When tapping the next actions field a list of option will be displayed. You can choose the appropriate label from the list to apply to your task.
Choosing the label "next action" will move the task with that designation to the top of the task list inside of the project.
If your project was set to use parallel next actions you can designate multiple tasks as the next action and all will move to the top of the list inside of the project.
If your project is set to sequential then you can only have one task designated as a next action at a time.
Please contact support with any further questions that you may have.