In a Run Process Menu, upon clicking on it, it will normally bring up an empty form as the following.
However, we can start a new process instance by referencing it to an existing record. To do so, we will need to modify the address of the page by adding "recordId" parameter and with the primary key of the record.
For example, the current URL is
http://localhost:8080/jw/web/userview/demo/v/_/request_submit
Change it to
http://localhost:8080/jw/web/userview/demo/v/_/request_submit?recordId=0df70dca-d51f-4c8d-9de1-2e3e9c0dc0c2