AWS SES is supported. Follow this document from Amazon on how to obtain your credentials. Using Yarkon Admin Console, choose the Administration option from the sidebar, then select the Mail tab. Choose SES for the service type, this will automatically use the correct port and TLS settings. The SMTP endpoints (hosts) for SES are listed here; use the appropriate endpoint for the Server Name. Use the aforementioned SMTP credentials for the Username and Password. The Send From field must be a verified email address you can send from. Use the Display Name field to add a user friendly name.
Note that the sender email must be approved by AWS SES before it can be used to send outbound email.
In the image below you can see the Yarkon Admin Console set up to use an AWS SES endpoint.
You can use Gmail as your SMTP server, but you should not. Even though Gmail is the fastest way to get started with sending emails, it is by no means a preferable solution. Gmail expects the user to be an actual user and not a robot/application, so it runs heuristics for every login attempt and blocks anything that looks suspicious. Being that this is a business product, having access to an Email server is expected and required. Use the same Email server you use for your other automated emails.