To add most Gmail accounts, you can just add your Login Credentials, but with business managed G-Mail Accounts you need "Manual Configuration"
FIRST! Configure G-Mail for IMAP by logging into G-Mail via browser!
Fire up outlook and go to Add New Account.
Manual Setup >> POP or IMAP
Now fill in details like below, make sure to fill in entire email for Login Credentials!
Now select More Settings
Leave General As-Is
Outgoing Server >> Check My Outgoing Server requires authentication
Advanced >> Incoming Server 993 >> SSL && Outgoing Server >> 465 SSL
Test! You may need to toggle with Secure Password Auth (SPA) Depending on organization!