Stored Procedures & Functions on the Diagram

Stored procedures and functions can now live alongside the other database objects on a diagram. This gives users the ability to go beyond relational models and document dataflows, transformations, and pipelines.

how can i use this function?

I am free trial mode, but I coldn't find this new feature 

Hello, thanks for contacting Support.This is functionality that is available on our Enterprise plans only, unfortunately.