Access your account ( as you always do, click in the cogwheel in the right superior side and then click on Options.
Click over the option Your e-mail accounts.
Search for the button Add a send and receive account and click on it.
Fill out the information by giving it your password and the webmail address you wish to set up and click on Next.
Finally select where you want to receive the e-mails of your webmail and click on Save and it is done and you can check your professional e-mail from your hotmail inbox.