XDA-forums original Archidroid thread for Samsung Galaxy S3 (GT-I9300): [ROM] [4.4.4] [CyanogenMod] [Linaro 4.9] [Excellent] [06/09/14] ArchiDroid V2.5.3
Currently the stable version is version 2.3.5, and I wanted to go with the 3.0.1 experimental version, and here’s how to do just that:
1. Go to the Archidroid’s github repository: i9300-cm-experimental
2. And download the repository zip: direct download zip of i9300-cm-experimental
3. After the download is finished, unzip the archive.
4. Download 7zip from here: 7zip.org
5. After you’ve extracted the i9300-cm-experimental zip archive, go into the directory, select everything (Ctrl+A shortcut) and right click and select 7zip > Add to archive… and select Compression Level: Fastest and the Compression method: Deflate and click ok.
6. After the zip archive has been created, copy it to your device.
7. Next, just reboot your GS3 into recovery console and flash the .zip archive like any other rom.
A short video available on the Archidroid thread which shows some of the steps mentioned above: