how to configure to use postmaster to monitor emails sent thru ses?

Firstly, configuring SPF involves updating your domain's DNS records. SPF helps in validating that the emails sent from your domain are coming from authorized servers, like Amazon SES. If you're starting without an SPF record, you'll need to create one with the entry v=spf1 include:amazonses.com -all. For domains with an existing SPF record, simply add include:amazonses.com to it. This modification ensures that emails sent via Amazon SES are recognized as legitimate by the recipient's email servers

https://dmarcly.com/blog/how-to-set-up-spf-and-dkim-for-amazon-ses

In parallel, setting up DKIM for Amazon SES involves adding specific CNAME records to your domain's DNS settings. These records are provided by Amazon SES and are unique to your domain. They function by adding a digital signature to your emails, which email providers use to verify that the emails are indeed sent from your domain and haven't been tampered with. Post this setup, you should see “Enabled” & “Verified” statuses in your Amazon SES console, indicating a successful configuration​

https://easydmarc.com/blog/amazonses-spf-and-dkim-setup-step-by-step/