First thing you need to do is go to the LDP (there is a link in internet links) and read the kernel howto. Then, install the kernel source with corel update, or download the latest kernel (stick with a stable kernel). Here is an excerpt from the howto:
It's best to use ftp.xx.kernel.org where xx is your country code; examples being ftp.at.kernel.org for Austria, and ftp.us.kernel.org for the United States.

First of all, a custom kernel will not have drivers for hardware you do not use. This means a smaller and faster kernel. Also, if a device is not supported, compiling a newer, or just custom kernel might make that device work. Also, If you need to build any device modules for your kernel, you will need the kernel headers. Unfortunately, at the time I am writing this, the kernel headers that ship with corel do not match the kernel image. Thats not really all that big a deal, a quick re-compile and you are all set.