Open one of the Microsoft apps, in this case Word. Click the Sign in link located at the top right of the app.
Sign in using your Office 365 email address.
Click the Work or school account option.
Type in your Office 365 password and click the sign in button.
If prompted as here, click the Yes button.
Success! Now click the Done button.
In Word (or other Microsoft Office apps, click Open and you should now see all your
Onedrive for business files and storage.