Subscribed calendars update automatically. A calendar added with the "Google Calendar" button is kept in sync by bandori.fans itself. Apple and Outlook each decide how often to refresh — it can take a few hours, sometimes more than a day.
Google Calendar: this button always subscribes to every category — it does not follow "Feed contents" above. For only some categories, use Apple Calendar or Outlook, or copy the feed URL.
Google Calendar · Android: if the button opens the Google Calendar app, add the calendar as it asks and it shows up in the app — no need to turn on Sync. If it opens Google Calendar on the web instead, or you add it on a computer, the app keeps it hidden until you open Menu → Settings → the calendar starting with "All bands", and turn on Sync. If nothing asks you to add it, add it on a computer.
Google Calendar · iPhone, iPad: the Google Calendar app can't subscribe — add it on a computer, or use Apple Calendar.
Google Calendar · if you subscribed before: your old calendar is not replaced, so with both you would see every event twice. In Google Calendar's Settings, pick the old calendar starting with bandori.fans and choose Unsubscribe. The new one starts with "All bands".
Apple Calendar: only iPhone, iPad and Mac show the subscribe prompt. On other devices, use a computer: add the feed URL above to your calendar by URL.
Outlook · Android: subscribe once on a computer — Outlook on the web → Calendar → Add calendar → Subscribe from web → paste the feed URL above.
How to add (click to expand)
Click "Google Calendar". If you are signed out, Google's sign-in comes first; then follow the prompts to add the calendar
Or, on a computer: Google Calendar → + next to Other calendars → From URL → paste link
Android: if you added it in the Google Calendar app, you are done. If you added it on the web or on a computer, open the app → Menu → Settings → that calendar → turn on Sync. The button's calendar starts with "All bands", one added by URL in the step before with bandori.fans (tap Show more if it is not listed)
On an iPhone, iPad or Mac, click "Apple Calendar" and confirm the subscription in the prompt
macOS: Calendar → File → New Subscription → paste link
On a computer: click "Outlook personal" for personal accounts such as Outlook.com or Hotmail, or "Outlook work/school" for work or school Microsoft 365 accounts. If you are signed out, Microsoft's sign-in comes first and may ask you to pick an account; then confirm adding the calendar
Or, on a computer: Outlook on the web → Calendar → Add calendar → Subscribe from web → paste link