Hello André, thank you for your response. It turns out that I don’t have Odoo installed on an external server, but on Odoo’s hosting, so I believe I can’t create a new method (or can I?). Could you please give me some guidance on how to grant permissions to my user? I have changed the body of my request, and it shows an error stating that the method I am trying to use is private.

Thank you.

Have a look at how to use the API. The documentation helps a little bit.
Pay attention to the version of your Odoo instance.

The most important thing regarding API calls is to understand the Odoo object structure, and how you can call actions, depending on the model, and fields of the record. 

The second part is regarding permissions. 
Your user must have permission to call the objects, or you must set a workaround on the server side,(create a new method or cal)l, that lets you access the information you want to access from the API.