Start human task from REST api

Hi
I have a human task on my cmmn model, which I need to make available on api call
It should not be available when I load my spring-boot application.
I tried using manual activation, but the task is not available in list when query using taskService.
I don’t want to create a human task programmatically, rather have it on my case model and start it using java code. any thoughts, Please?