Check the guide to see if there's a step you forgot to do: https://docs.google.com/document/d/1LkXWll0_8kVL23hHWWySoRwKL_4dyluPHeLQsnhvwuE/...
Edit: If Anna only mentions wanting to do the magazine then you're still early on in the process. I think you need to continue playing the game until you visit her again at the kitchen where she shows you the magazine and is mad that she's been overshadowed by Celeste on the cover. From there she'll want to do livestreaming, which you'll find out how that goes.