When you use the TriggerPipeline native step in a pipeline, it performs the functions shown below in the background. For more information on TriggerPipeline Pipeline steps, see TriggerPipeline.
GET /projects (if projectKey is provided, the projectId is found)
GET /pipelines (find the pipeline by its name)
GET /pipelineSteps (find the step by its name)
POST /pipelineSteps/:id/trigger (trigger a run starting from the specified step)
GET /runs/:id (poll the run to check its status)