is there any video or document on how to solder the SIM900 type ICs to pcb? it has strange under body soldering pads that iam confused on how to solder .
On the top side you can see the contact for solder. I think it is soldered on component side itself like SMD components. You can solder using SMD soldering. You PCD pads should be a little longer such that the bottom pads of SIM900 sit on it and also a portion of the PCB pad is available to solder from the outside.