The following guides have been taken from: https://support.office.com/en-gb/article/Office-2016-Quick-Start-Guides
Visit http://email.chichester.ac.uk (Chichester email address)
Or https://mail.office365.com (Crawley email address)
Login into using your usual college login details
Click the 'Waffle' in the top left corner
Click Office 365 in the box that opens up
Click on the ‘Install Office apps’ on the top right
It will download the installer and off you go!