You will need to sign up for a Washington Post account with your VMI email address. Other email addresses such as gmail.com will not work. Once you've signed up for an account, unless you save the account username and password in your browser, you will be asked to enter that information every time you go to the Washington Post.
Note: you can add the Washington Post app on your mobile device and access it there -- too!
Note: these are approximate directions, and can change.