Kernel Recompiling (selecting kernel modules)

Hi,

Today I succesfully built my kernel according to the instructions at: http://www.angstrom-distribution.org/building-angstrom

Now, I am wondering how do you choose which kernel modules to include or to remove to your new kernel? For example I want to add usb to serial module which will help me to connect to serial port from the beaglebone with the following command: screen /dev/ttyUSBx. I searched over the many topics but it seems like everybody except me knows what is required to be done. Could you please explain me step by step how do you recompile your kernel according to your needs?

Regards,
Amadeus