Writing the Body of HTTP Trigger LogikApp

I need to read the title of any new Task from a Planner then put a number(from SharePoint list) in front of the title and then patch the title. Any Ideas how i can just get the new Tasks from a planner and i don't know how to write the Body properly to batch my title as well the number from the list. Does anyone have good Learning Material on writing the Body. Just OData and entities in general would be nice.

I am interested in your replies.