Set up new variables e.g. Chapter1_Viewed, Chapter2_Viewed etc. (with an initial value of 0)At the end of each chapter moify the relevant variable to be equal 1 (i.e. seen)On your last page have your 'completed' action only activate if the conditions meet chapter1_viewed = 1, chapter2_viewed = 1 etc.You could use another action group to list the chapters that are still to be visited to help the user.
