This video explains the detailed steps on how to start and stop linear task flow via Rest API.

References
KB Article:
https://knowledge.informatica.com/s/article/HOW-TO-Start-Stop-a-Linear-Task-flow-execution-using-Rest-API-in-CDI?language=en_US

Rest API Doc:
https://docs.informatica.com/cloud-common-services/administrator/current-version/rest-api-reference/platform-rest-api-version-2-resources/jobs.html