there is no thing on the side for a sim card only volume buttons :s can any1 help me please?

Are you talking about an iPad or an iPhone? If an iPhone, what model and where did you get it? The CDMA (Sprint and Verizon) iPhone 4 does not have a SIM slot.

On an iPad 2, the SIM tray would be on the side opposite of the volume buttons. If there is no sim tray, then you either have a Verizon 3G model, or a WIFI only model.