you have to reach a certain level, you will then unlock create a class which allows you to set up your weapons, attachments, and perks any way you want (you have to get higher in levels to unlock more guns and perks)
I think he was asking how we set up our classes. Me i got a m1a1 with bomb squad Stopping power(or Jugg) And dead silence.
Or Mp40 Dual mag jugg and Dead silence.