Hey spejoku, thanks for the question! You can find the documentation for the Turn Based Movement plugin in the help section of the JS file itself. For some reason that does not seem to be showing up in the Plugin Manager, so I'll repost the helpfile in image form here. We will release a patch that fixes this issue soon.
To alter an Event's speed, you would need to change the settings in the Autonomous Movement section of the Event Page. This can also be done via Set Movement Route's Change Speed option or via script call.
Hope this helps. Please feel free to ask any other questions you may have :)