Candy Cake

My niece is turning three tomorrow and I promised her that I will make a delicious candy cake for her and her friends. It is a challenge for me because I have never put candies on a cake. I am not sure that I can decorate this cake so I need you to give me some advises. Teach me how to decorate the cake with colorful and delicious candies. Make sure we do not forget about the chocolate because it is her favorite. Decorate the best candy cake for my niece and for her friends!