The Routines segment of the Workouts tab is your routine library — every plan you can start, tap to edit, and see at a glance.
Each card shows a routine's name, how many exercises it has, and a small muscle map of what it trains (in brand orange — this is what the routine is designed to hit, not how recovered you are; that's a different color on Dashboard). Tap the card to open and edit it; tap ▶ to start that workout right now.

Nothing here mutates your history — starting a routine just loads its current targets into a new session; editing a routine only changes what happens next time you start it.
Related: "Routine detail", "Starting a workout off-plan (Quick Workout)", "Attempt a record", "Named programs", "Logging a workout"