If you already have a running ruby installation, you can install watobo via 'gem'
.
c:\>
gem install watobo
This might take some time ...
To start watobo enter
c:\>
watobo_gui
This
video will show you the full installation, including Ruby, DevKit & watobo.
Note:
Other than as stated in the video, you can use any ruby version > 1.9.3