Hey,
Inside logic tab,goto Integration section, under that go to api ,right click and choose consume option.popup will open and ask for single or multiple method to add,choose single if you want to consume individual. In input add api url ,choose type of api(get,post etc) and inside body add your Json formated data.then click on test button ,if you receive response then click on ok button button then outsystem will automatically create input object for your api.
https://success.outsystems.com/Documentation/11/Extensibility_and_Integration/REST/Consume_REST_APIs
Hope you will understand.
Thanks
Yogesh