To generate a preventive task by iteration, you must go to the task, then to subtasks and click on the option “Set as a cyclical task” as shown below:

Define the number of iterations in which the cycle will be completed

Define the subtasks and the iterations in which they'll be activated respectively. The name of iterations can also be changed

Once all subtasks have been created, we will be able to see in which of the iterations they’ll be activated.

You will also be able to define the resources to be used in different iterations.

Finally, just click Save.