how to use a normal 2.5 HDD for xbox 360 slim?

hi there guy,

my brother has just got a 360/kinect 4gb bundle, and he wants to get more space, i know where you can insert a new HDD and that 2.5 sata can be used with a special plastic case, i just wanted to know if i have to format the HDD in a sertain way, since i got my old laptop HDD and i wantd to use that one for him.

i checked the youtube but it was mostly filled with how to use ur old xbox HDD on the new slim ones.

thanks