The Flowfield compares the position of your particles with the position of its flowLocators. By checking their rotation it pushes the particles in the corresponding direction. The influence of each flowLocator is scaled by it's transform-node's scaling.
-copy the .mel-files to your ..mayascripts-folder
-copy the .mll-file to your MAYA_INSTALL_PATHbinplug-ins-folder
-load the plugin (Window -> Settings/Preferences -> Plug-In Manager -> ds_flowField.mll)
-select a particle-object
-do "Fields -> Create Flow-Field"
-while having the flowField selected add as many flow-locators with "Fields -> Add Flow-Locator"
-move, rotate and scale your flowLocators until you get the effect that you want
if you discover any problems / bugs or if you just like it please tell me!