I want to plug my laptop into my mixer to use virtual dj software but Orse I plug the laptop in one of my among my mixer has toujour it as a sound (uuuuuuuummmmmmmmmmmmm) I want to know however the c is and how to be able to mix with my pro 200 and my lap top

here is my set up
american dj pro 200 mk II
mixer
amp
thank you al advance

ps which dj software is the best