In order for your integration to get notified when requests and conversations are updated, completed or changing, your project entity needs to have a webhook where you can be notified with the payload.
Go to your project page and you will find the Webhook section where you can define a value. After that value is defined you can click save.
As you develop your integration having multiple environments is something that is crucial for you to be able to test against. To achieve that, you should define multiple projects for each environment and save a differnet webhook value for each of of them. That way, requests created from one environment will not interfere or get mangled with the ones from the production environment for example.