Exactly what it says on the tin. These are instructions from Raspi.TV on how to download and write an operating system image onto an SD card for the Raspberry Pi.

A couple of teachers asked me to do some instructions for them at the Milton Keynes Jam on how to download and install the OS for the Pi. They have to get incredibly good at this task as they will likely have to carry out this process several times a week, what with students tinkering and messing up! 🙂
Alex at Raspi.TV has done a great job on some instructions and so, rather than re-invent the wheel, I thought I would just point people at it.

Visit the link below for the instructions:
http://raspi.tv/2012/how-to-make-a-raspberry-pi-disk-image-to-sd-card-with-win32diskimager