Before you can download and install the Office apps, you will need to have a license added to your account by IT. You can request a license from the help desk.
Navigate in a web browser to https://portal.office.com.
At the top right corner of the page should be a button to "Install Office".
Click on the button. If the option "Office 365 Apps" is not available, the license is not applied to your account. Send a request to helpdesk@gemission.org to have it added to your account.
Clicking on "Office 365 Apps" will download the installer. Run the installer once downloaded and follow the prompts to install office on your computer.