Reply to Soundcard and headphone problem

Hello there, I am trying to get the sound through my headphones when I use my soundcard and plug my headphones to it as I don't have studio monitors yet. Problem is, I couldn't get any sound to me headphones.

Is it the soundcard? I am using the one I use for DJ. Numark DJ I/O

or if its the settings what shall I do? I am using FL studio 10.

Thanks.