If you've been assigned a shoebox diorama for a book report, you will need to create a scene from the book in three-dimensional picture form. That means that the people in your scene are going to have to stand up. By attaching them to your shoebox in a pyramid shape, you can make them stable enough that they won't fall over during the trip to school or while they're on display in your classroom.
Fold your piece of card stock paper in half, and turn it so the fold is at the top. Your person's head is going to be by the crease, so make sure you have enough room under it for your person.
Draw your person on the card stock. Put his head at the top, touching the fold, and his feet at the bottom. Leave about 1/4 inch of space on the paper under his feet. Create his features and clothes using the markers or colored pencils.
With the card stock still folded, cut your person out. Do not cut across the crease at the top, and do not cut off the extra 1/4 inch of paper below the feet. When you have finished, you should have two layers of card-stock in the shape of your person, joined at the top of the head.
Separate (or open) the two layers so that they are about 1/2 inch apart at the bottom.
Fold the 1/4 inch excess card stock at the feet inwards, creating a pyramid with the folded-in tabs as the base.
Glue the foot tabs to the floor of your diorama, with the colored side of your person facing front. This will allow your character to stand very stably.
TL;DR (Too Long; Didn't Read)
Draw and color your person completely before you stand him up.