The definitions are straight forward and simple. You just setup the url parameters for each rule and if they match, caching will be turned off for any page that is called with these parameters.
For detailed instructions please install the plugin and have a look at the available options.
Actually I was going to give less rating for the lack of documentation, but I figure out how to use it in the first try.
By entering "event=submit" in the configuration textbox I was able to achieve the wanted results. A bit more documentation (in the plugin or on the website) would've been helpful, but overall a good plugin.