Teen Challenge does not have a training course developed for this subject at this time.
The following link will take you to an extensive online library of resources designed to help non-profit organizations.
http://www.managementhelp.org/plan_dec/str_plan/stmnts.htm#
Just a few of the topics covered are:
Basics in Developing a Mission Statement,
Basics in Developing a Vision Statement,
Basics in Developing a Values Statement