How do I add a character?

At the start of every new scene, there are two characters facing the camera.  You can adjust those two characters to be anyone in your cast.

However, you can add more characters.

To add a character, go to 2D mode. 

Tap the pencil in the top right corner.

You can tap the character symbol and a person will appear somewhere random on your set, or you can draw a circle in the location you prefer. 

When you're satisfied with the amount of objects you've added, tap 'Done' in the top right corner.

Note the body type of each new person is randomized.  This feature is helpful for when you are creating a crowd of people or extras in a public place.