Business Process Management

I am still experimenting with CUBA.platform and I am trying to Business process management a screen that shall be displayed by clicking a button I have added to an existing& Editing a generic view(i have create start process button that’s not executed and business process also not starting)
I was took Contract Editor Screen Layout in this i.e(Contract Editor Screen Layout - CUBA Platform. BPM subsystem)
i.e Contract Editor Controller link(Contract Editor Controller - CUBA Platform. BPM subsystem).Business process management quick start video and tutorials many difference is there.I need one clarification.

This is a my form.xml code is that form action is not supporting to the start events inside a start form action . (2.2 KB).

give me a some suggestions.