Hi Guys

I would like to ask about talk designer. I made a 30 sec video with 2 characters.I was going to put 2 different sound file for this 2 characters. But it was not possible only 1 character can use a sound file with a same time.So the other one is can not talk in same time. How can I handle this situation? I mean how these characters can talk each other? Or I have to buy a plugin or something else?

Thank you guys.