Where is the technical documentation for setting up webhooks?

Where is the technical documentation for setting up webhooks?

Hi,
I want to setup some webhooks from ZohoBooks to my server.
Where can I find the technical documentation for webhooks?

I need details like,
  1. What is the expected response to mark a webhook as success?
  2. Threshold response time before ZB marks a webhook as failure
  3. Are failed webhooks retried? If yes,
    1. How many times?
    2. Time gap between each retry
  4. What is the meaning of the "skipped" status of a webhook? under what conditions a webhook is marked as skipped?