How do you make brushing teeth a fun time for toddlers?

I get a toothbrush in the cartoon that my son like and chose by himself together along with a toothpaste (it comes in a set). We also got him an animal toothbrush holder and cup. But when he started brushing I did not let him use a toothpaste after the first time he tried. He didn't know how to spit out and he swallowed the toothpaste. Only let him use toothpaste after he knows how to spit out.