You will need to have a calendar set up in Yahoo and Windows 8 signed in to your Microsoft Account. For more information
on setting up Microsoft Accounts, visit http://windows.microsoft.com/en-us/windows-8/microsoft-account-tutorial.
1. Share your Yahoo Calendar.
2. Log in to https://calendar.yahoo.com.
3 In the left-hand column under Calendars, you should find the name of your calendar (such as Benjamin's_Calendar).
4. Click on the gear symbol on the right to Manage Calendars.
5. Choose "Share..." from the options that appear.
6. In the "Share..." popup box, choose the calendar you want to share, and click "Continue."
7. Find the "Share with iCal Address" section and copy the web address. It will look something like
8. Click "Save."
9. Link your Yahoo Calendar to your Windows Live Calendar.
10. Login to https://calendar.live.com.
11. Along the top menu bar click the "Import" option.
12. In the lefthand menu bar, choose "Subscribe."
13. In "Calendar URL" paste the iCal link you copied from Yahoo in Step #7.
13. Give your calendar a name and select a color for your Yahoo events.
14. Click "Subscribe."
15. You should now see your events from Yahoo Calendar in Windows Live Calendar.
16. Open your Windows 8 Calendar app.
17. Press F5 to sync the app with your Windows Live account.
18. You should now see your Yahoo Calendar events in the Windows 8 Calendar app.
19. If your Yahoo Calendar events from Windows Live don't appear, make sure Windows 8 is signed in to your Microsoft
20. Using the Charms menu or Windows Key-I, open "Settings."
20. At the bottom of this menu, choose "Change PC Settings."
21. Choose "Accounts." You should see your user name and the e-mail address you used to sign up for your Microsoft Account.
22. If you are not signed in to your Microsoft Account, select "Sign in to your Microsoft Account" and complete the sign-in process.
Let me know if this works for you, and if you have any changes to the above instructions.