If you buy a 8830 in the US from Verizon it will not come with a SIM card. I have also read that it will not work with a SIM card in the US because there is some kind of interference between CDMA and GSM. The SIM card option is only for use outside the US on a Verizon phone.
As to the mechanics of the SIM card....If you can manage to pry the battery door off the back of the 8830 without pulling a finger nail off or cracking the screen you insert the SIM card under the Micro SD card fold out carrier.
I hope this helps.