وَالْيَوْمِ الْآخِرِ names belief in the Last Day, which gives human actions a horizon of accountability.
وَتُؤْمِنَ بِالْقَدَرِ خَيْرِهِ وَشَرِّهِ includes belief in divine decree, its good and its bad. In خَيْرِهِ وَشَرِّهِ, the attached pronouns refer back to decree.
Belief in divine decree does not eliminate a person's duty to act responsibly or strive to do right. For a beginner the meaning of the text comes first; complex theological controversies and detailed philosophical questions need not be introduced into this introductory account.