Atlas MongoDB scraping - need help with the ServiceMonitor

Following this guide:
to configure Prometheus <-> Atlas MongoDB integration, we are
faced with the need to configure our Prometheus Operator instance to
insert the required snippet into the scrape_configs section of the
Prometheus.yml file.

We think it will be required to create a new ServiceMonitor object to add the external Atlas MongoDB scraping config.Could someone here provide us with some guidance/help to tackle this?