The Night Qualification course will build on the skills you learnt as part of your PPL and adapt them for use in darkness. Once issued you can fly with or without passengers (subject to currency requirements) and take advantage of the generally smoother and less windy conditions that prevail at night.
Before starting the night rating you will need to have a PPL with a valid SEP(L) Single-Engine Piston (land) rating and a medical with no restrictions regarding flying at night.
If you are training toward your PPL and the conditions match, you may be able to do the Night Qualification during your PPL training. Although the authority states no official ground school is required, your instructor will guide you through the various human performance, air law and technical aspects of flight at night.