I'm not sure which modem you're trying to use. I understand is a Telit* CDMA modem, however I understand that there are a few of them.
Anyway, if it uses the PCIe socket, then I'm pretty sure that you'd have to make kernel modification, if the kernel is even compatible with the module you're trying to use. After this you'd have to search for the module's driver, if it even exists or if it is public. So to sum up , I believe this is a possible task however not the easiest one. If you decide to continue, a good starting point would be on Intel® Quark SoC BSP Build Guide.
Thanks for your reply , Yes it's Telit CDMA Verizon Modem and i will go through the guide that you sent to review it but from the first look at it , i wonder if i can communicate with the modem through *.h library directly instead of using SD card images , because i will use the SD-card later just for storage only not as boot loader , i reviewed some articles and they use GSM.h to communicate with GSM modem so i am look to find library for CDMA.
As I mentioned I my previous post as long as you need to use the PCIe socket you will have to maker kernel modification to the Galileo's image. But if the module has any other interface (I2C, UART, SPI, etc) compatible with the Galileo, then you could be able to interact with your module without making any major modifications. So it pretty much depends on your module's hardware.