help needed with manual Firwmare update - Alpha update

I want to try the new Alpha Firmware for my 2S , somehow I don't get the update instructions that is in the Readme : 

To backdate: find the 'SystemBackdate_X.XX' folder and copy the "GUPDATE.GCD" file to the Garmin folder of your watch.
Then unplug and install. Your watch will begin the backdate process. Backdating software will revert your watch to factory default.

Please note: the software update folders above include a secure_config.gcd file, which should also be installed to your watch. This file helps automatically generate some files if you encounter certain issues. In short, if you are using alpha or beta software, you should also always have this file installed: it will make your use of the watch easier, and make it easier for you to report issues in software. 

The secure_config.gcd file should be installed to the Primary\Garmin\RemoteSW folder on your watch.

I have done step 2 and if I understand it right the "SystemBackdate" is just if I need to reverse ? Could be wrong here, can anyone walk me a bit more in detail, which file needs to go where ? 

thanks