Questions About Control Over Plugin

Hello,

I downloaded this plugin for the purpose of moving old posts up to the top of my RSS feed, but I have a few questions first…

1) How exactly does this work? For example, does this plugin AUTOMATICALLY update old posts without you having to do anything? Or… do you have to take MANUAL actions to republish old posts?

2) Do I have any control of WHICH posts are republished and when?

3) Most of my posts are older than 6 months. Will this work with the free version of the plugin?

Thanks.
Ethan