If you got enough computer space, simply go to your RO folder c -> program files -> gravity, there you will see the "RO" folder. Copy and Paste it, rename it to RO2, now you have your other server in RO folder, install the september patch of heRO in the RO2 folder.
Use hero.exe in RO2 folder to play on heRO (you can create a shortcut and drag it to your desktop for easy access).
If that's not clear let me know where you blocked and we'll try to help you solve it ^_^
