Cardboard Box Modelling

First, I created the cube and adjusted the edges and vertices accordingly.

Then, I selected the top face of the cube and extrude it to the bottom of the cube.

After that I selected the faces at the sides and extrude them upwards.

I also selected edge ring tool for different sides of the cardboard.

In the end, I created the wave on each end of the flaps and smoothed the cardbox.

Reflection:

Cardboard modeling was QUITE challenging for me. It was difficult to grasp what the instructions on the PDF files were trying to say. So I did as much and tried to make the cardboard look as alike to the one on the PDF file as much as possible.