How can I make image that runs on emmc (Angstrom)

Thanks for your attention.
These days I try my best to install a new linux system on my BBB emmc,However,I meet many mistakes.
I just want to make image like Angstrom Distribution (BeagleBone Black - 2GB eMMC) 2013-06-20.
I did my image as follows:

  1. I install A cross compiler。
    2.build the uboot
    3.download the kernel.
    4.compiler the kernel.

the questions are:
I just find the files:uImage.u-boot.MLO.
I cannt find the rootfs.
The another question is How can I put the above files into one Image just for eMMC.
Thanks again.

http://www.elinux.org/Beagleboard:Updating_The_Software

Gerald