0. Download & Install TurtoiseSVN for Windows.
1. Download MC Launcher, Run it once & close it. 
2. Browse to your %appdata% folder, then open up .minecraft folder and delete the content of it.
3. Right click .minecraft folder and do SVN Checkout, copy & paste this repository in the checkout window and hit OK: http://alcemycraft.googlecode.com/svn/trunk/
4. Once the download is finished, run MC Launcher again, make sure the forge profile is selected then hit the Play button and you're good to go!