Follow these instructions to sync your community-branded email account with Apple's Mail app on macOS.
Open Apple's Mail app and begin by clicking the "Add Account..." from the menu options.
Choose "Other Mail Account..." and continue.
Enter your account details and click "Sign In."
Fill out the additional settings as seen below, making sure the "User Name" is filled out; then, click the "Sign In" button.
Uncheck "Notes" and click "Done."