If you don't want to use the web version of GMail - http://mail.oakgrove.school - you can add it to Outlook.
On school machines, this is done using the G Suite Sync software.
1. Make sure Outlook is closed and open Set up a G Suite Sync User from start > g suite sync
2. Enter your @oakgrove.school email address and click Continue. A browser will open and take you to a google login.
3. Log in to your google account with your email address and password
4. If it asks, say that yes, it's your account and when it asks for access to your google account, scroll to the bottom and click Allow
5. It will tell you that Authorisation has been granted successfully. Please switch to your application. The g suite sync application in the taskbar at the bottom will have gone Orange, click on it to switch back to that app.
6. Click Create profile
7. Then click Start Microsoft Outlook
Microsoft Outlook will open and your email account will be added. It will initially download a quantity of previous emails, so can be a little sluggish.
You will also want to set your default address book to the Global Address List. That can be done using this guide - https://kethelp.freshdesk.com/support/solutions/articles/47001149358-set-outlook-default-address-book-to-gmail-global-address-list