Talent Sourcing Strategy and process

I am a Consultant, I am looking to create a strategic Talent attraction and acquisition process for a large organization. I am looking for someone to conduct research and prepare a presentation on how do organizations recruit for executive and senior levels, what kind of processes (including details of the process/assessment tools/sources to do they use to identify talent (how do they identify and connect with different levels of employees), assess them. Who approves for which level. How are they leveraging marketing techniques to create brand ambassadorship. This in the context of modern day HR where data analytics and social media plays a role. Preferably for a large sized organization. To what extent are companies going for internal vs external sourcing etc