You can download an Angstrom image from a couple of sources:
- http://www.angstrom-distribution.org/demo/beaglebone/ (you’ll probably want to use the first image listed on the page)
Both pages include instructions for copying the image to an SD card. If you do things the easy way then the install process will handle the partitioning of the SD card for you – if you prefer to handle the partitioning yourself, follow “the hard way” instructions on the 2nd page.
The images from the 2 sites are similar: the first is easier to install if you have a Windows PC, and the 2nd is easier from a Linux PC.