Understanding Shopify webhooks for app development: Any tips?

[sharma01]

Hi I am new to shopify app development (using shopify cli, node, javascript) and am facing issues with shopify webhooks, I am connecting with amazon event bus but the payload always seem to be a custom payload for each webhook subscription. My goal is to get a custom payload in json format and then push the data into a cloud database. 
I have read the dev docs but am not able to understand the working. Any help is appreciated.