I did this for my outlook account for school too!
You first need to go to your outlook email account and sign in. click on "options" at the top right corner and then click "See All Options". In the Account section, there should be a link at the bottom that says "Settings for POP, IMAP, and SMTP access". Click that and it will pop up with the information you need to type in. Once you get that information, add another email account on your phone.
You're going to select the "others" email option so that it lets you set it up. after you put in your email and password, input the information from Outlook. For example:
Type: POP or anything else similar to POP
Servername: pod51000.outlook.com
Port: 995
Encryption: SSL
Then it'll ask you for outgoing mail (SMTP), where you will input the following:
Server: pod51000.outlook.com
Port: 560
Encryption: TSL