Values are important and enduring beliefs or ideals shared by the members of a culture about what is good or desirable and what is not. Values exert major influence on the behavior of an individual and serve as broad guidelines in all situations
Our personal core values make us who we are and will dictate how we will react to life in general.
The best way to do this exercise is to not overthink and to do it somewhat quickly. Go with your gut-feelings. Be as honest as possible. Don't focus on who you would like to be but focus rather on who you are right now at this moment in time.
http://www.mypersonalimprovement.com/personalcorevalues.shtml