SSO authentication to Flowable

I am try to implement workflow using flowable in my own application.
User logged in to my application using SSO authentication, when he clicks a button it should trigger flowable process using same SSO authentication as I use to login to my application.
I want to skin flowable GUI and want to expose all functionalities of flowable in my own app using flowable REST api and Angular JS forms.I am using spring boot for flowable application development.
I need help to start with that.

It seems something related to Spring Security more than flowable.

Have a look here to have some insight.