Cloud codes are currently only available for POST requests and you have to define them using Parse.Cloud.define method.
They will be available in https://parseapi.back4app.com/functions/YOUR_FUNCTION_NAME. You have to send your appId and keys in the reader and the parameters in the body. You can use console located in dashboard to test it.
You can find more information in the link below:
https://parse.com/docs/cloudcode/guide#cloud-code-cloud-functions