It is easy to add as many Milestones as you want to support your Objectives and its Strategy. Milestones are markers in time that show progress against your Strategy. They are not daily to do items. Rather they are key points in your Strategy that can be mapped to a date.
As you achieve the Milestones your Dashboard will show progress towards your Objective.
When you are done creating Milestones you can press "Close" on the pop up.
Once your Milestones are defined they will show up as a list below your Objectives, Strategy, and Goal.