Need help getting a plugin to run

I downloaded and installed the plugin called “user submitted posts” because I want people that come to my page to be able to post what they have to say (my site is ilovetowalk.com), I wrote to the author but he never has gotten back to me, I read his readme.txt file but it doesn’t make any sense at all, he talk about template tags and shortcodes, but I don’t know what they are or how they work. I’ve installed wordpress on several sites, and they seemed to work, but I don’t know about this one.