Due Dates on steps (deadlines) are very similarly configured to executors.
To add a deadline to a step, select the step and you will see the properties window open adjacent to it.
Beneath the properties you will see the option to set a due date, click the plus to add a due date.
You can set a deadline based on the step initiation, post-step or based on a field within the collection.
Furthermore, you may add conditions to trigger a specific deadline type, such as priority or severity.
You can add multiple due dates per step and you should ensure that any such conditions are correct. Once a due date has passed, a step can still be completed and the record remains active.