How to Add Custom Assignment Block to Existing CRM Incident

Hi All,

I Have a requirement where I need to add the custom assignment block to the CRM Incident screen, for this, I developed the CRM WEB UI but do not got how to add it to the incident screen.

In the personalized screen of the CRM incident, where we can add and remove existing assignment blocks but I didn't find a custom assignment block.

Can someone help me with how to add the custom assignment block for the incident screen?