First, take a cardboard tube, or several tubes of various widths, and cut them horizontally into sizes long enough to be able to contain your small gifts.
Then, add some color to your tubes. Paint spray is probably the easiest and fastest.
Draw a triangle or form one with straight objects. This will create a tree shape outline to guide your calendar's layout.
Arrange the tubes inside the triangle and place the small gifts inside. When adding the Ferrero Rocher, remove the paper cups first.
Cover the tubes using Ferrero Rocher paper cups. You can even write the days of the Advent Calendar on top of them.