Regardless of which membership tier you are using on the app (Free, Premium Monthly, or Premium Annual), you will only be able to see workout details for the present week and next week. In other words, two weeks at a time.

You can always scroll down in your plan to see the general overview of your training for many months in advance, which includes an estimated time for each workout.  But you won't be able to open those workouts to see the details until you're at that week in your training cycle.