Start with the eligible-activities page
MOM’s directory provides a dedicated eligible-activities page for work that may be performed for a short period without a work pass. Its examples include journalism, exhibitions and sports, but the detailed page sets the scope and conditions for each activity.
Notification and extension are separate procedures
The notification page explains how to inform MOM of a work pass exempt activity. A separate extension page explains the requirements for extending an existing notification and how to do so. Confirm eligibility first; a notification is not a substitute for satisfying the activity rules.
Official source
Written independently from official MOM source material.