Hello charliejoseph,
Welcome to the Apple Support Communities!
I understand that you would like to set up and use your Yahoo! calendar on your iPad. To do this, the Yahoo! account will first need to be added to your iPad. If it is already set up, you can skip the first step to set up. This information is located on page 17 of the attached iPad User Guide.
Set up other mail, contacts, and calendar accounts
iPad works with Microsoft Exchange, and many of the most popular Internet-based mail, contacts, and calendar services.
Set up another account. Go to Settings > Mail, Contacts, Calendars > Add Account.
You can add contacts using an LDAP or CardDAV account, if your company or organization
supports it. See Add contacts on page 93.
You can add calendars using a CalDAV calendar account, and you can subscribe to iCalendar (.ics)
calendars or import them from Mail. See Use multiple calendars on page 78.
For information about setting up a Microsoft Exchange account in a corporate environment, see
Mail, Contacts, and Calendar on page 152.
Once you have the Yahoo! account on your iPad, you can turn on the calendar by following the next steps located in the same User Guide, page 78.
Turn on iCloud, Google, Exchange, or Yahoo! calendars. Go to Settings > Mail, Contacts, Calendars, tap an account, then turn on Calendar.
Have a great day
