To look up the specifics of each API call, just Google it!
Search “Zoho (your_app) API” and it should be the first result that appears. Using the API documentation, you can obtain the URL’s for each API call and learn what format and which permissions it needs.
Most Zoho app API documentation pages are similar, with the exception actually being the CRM API. However, with a little experience, you’ll become proficient at reading them and finding what you need.