It is pretty straightforward, but here ya go anyway:
- Connect your device to the PC.
- Launch BBSAK. Will probably ask you for a password. If you don't have one, just click OK.
- Choose the "Wipe Device" option.
- Wait for BBSAK to inform you it's finished. Your device will reboot and you'll be left with a white screen and an error 507, which means the wipe was successful.
- On your PC, navigate to C:\Program Files\Common Files\Research in Motion\AppLoader.
- If the OS is from your carrier you can skip this step, otherwise delete the file at the bottom called "vendor."
- Make sure your device is connected to the PC.
- In that same folder as above, you'll see an executable (4th or 5th item from the top) called Loader. Should have a little phone icon. Double click on that, which should start loading your OS.
- Let the loader do its thing and you should be good to go from there!