Adding a Calendar in the iOS Calendar App

iOS and iPadOS

Does anyone out there know how to add a calendar to the iOS calendar app. I'm thinking of an organization that does regular programming each Saturday from December to the middle of May, the Metropolitan Opera. I don't want to enter each show manually, but I'm also not sure if they have an app that will let me do this. It's their famous Saturday broadcast series.

I know a lot of people have done this with sports teams, so I thought I could do it with this event.

Here's my question: How do you do that? How do you subscribe to this kind of calendar. Do you need the organization's app to do that? Exactly what do I need to do? Thanks.