You can either buy BayRSS2.0 or download the lastest free version here → http://bayrss2.com

There's a link above to download BayRSS2.0 for WordPress (make sure you know where you've downloaded them to). Once you've done that, unzip it.

The entire plugin folder should be uploaded as-is to your WordPress installation, so that it ends up as wp-content/plugins/BayRSS.

You can also upload two files : bidnow.php and viewnow.php onto the root folder of your WordPress installation. 
If you are not sure where is the root folder, look out for the wp-config.php

Log into your WordPress control panel, go to “plugins”, and enable BayRSS. If you need more help installing WordPress plugins, check out the WordPress plugin installation instructions. From there, you can go to the new Settings → BayRSS panel and configure your default settings.

You will probably see this in the settings page :

Important Note: Double check that you have entered your EPN, AWS and Associate ID correctly.
Entering a wrong AWS will give error messages when you use the Amazon tag.

Once everything is setup correctly, BayRSS is now ready for deployment.