Dear Blessing,
For detail please refer ENA Manual on pages 12-14 (very detail explanation with examples is included).
i.e. Emergency Nutrition Assessment for Standardized Monitoring and Assessment of Relief and Transitions (ENA for SMART) Software User Manual ENA 2011, (Version 2011, July 31st, 2012), Final Version August 2012
Hoping it will help you.
Gezahegn Shimelis