Multiple steps:

1. update security settings in gmail
2. IF 2 factor is setup, then create an app password (instructions here)
3. IF no 2 factor is setup, then just allow app access (instructions here)
4. Once the above is done, then add in Control panel > Mail > create new account/profile

More resources:

New Resource:

https://www.lifewire.com/gmail-access-outlook-imap-1173659

Older Resource:

Gmail in Outlook: unable to connect to email

https://www.howtogeek.com/279384/how-to-secure-your-google-account/