Zurich is a very walkable city, with most landmarks centered in a relatively small area.
If you want to learn as you walk, you may find it more fun (and efficient) to join a guided walking tour, in which you’ll learn all about the rich history of this city and region. Zurich Tourism offers a 2 hour guided walking tour in English. It costs CHF 25/adult, 50% discount with Zurich Card.
We also like Free Walk Zurich, where you don’t have to sign up beforehand and you can tip what you want.
If you want a flexible schedule, try my self-guided Zurich walking tour that wander the cobblestone lanes of the old town. It visit all the famous landmarks included in my Things to Do.
I also have chocolate walking tour, which visits a bunch of chocolate shops as you explore the old town, particularly nice if you have kids in your group.
Plan about 90 mins to 2 hours, depending on how many stops you make at various landmarks and shops.