Here is the map with all the locations spotted, so you can freely choose which direction you’d prefer!
Be sure that you can fit all of them in one day. I’ve done it several times before! My preference would be starting with the Corso Buenos Aires, heading to the Rectangle of Gold (surely you can skip this two if you are not that volunteer for a fashion based activity) and then continuing through San Babila (redline) and reaching to Duomo Square. There, following the Galleria Vittorio Emanuele II you’ll reach to Brera Square and after that you can follow the way to Castello by walking or just taking a tram to head there. After Castello now it’s the perfect timing for an aperitivo and I’d prefer to go to Navigli in order to get my aperitivo choosing one of the different styled numerous bars! By the way you need to put the visit of The Last Supper according to your reservation time, thus I didn’t mention about it in my schedule.
BRAVO! You’ve just accomplished a wonderful one-day trip in Milan!