CTA itself does not have the ability to draw or create characters from scratch.
You must create the characters in another app and then load them into CTA and assemble.
Check out the many postings on YouTube on how to cartoon a picture using Photoshop.
The same techniques can be applied using almost any photo editor.
See my CTA Tutorials on the YouTube channel CTAStepByStep
Check out EZColors for CTA. The easy way to change Render Styled (RS) colors.