Adding code to 'blog-item.php'

I purchased the “WTI Like Post” plugin. I’m having trouble, however, in adding the necessary code to enable the plugin to show in my blog excerpts.

I’ve consulted with both the theme creators (Modernize Theme) and the WTI Like Post creator. Here’s what I have from them, but I don’t know code and am not sure where I’m supposed to add this stuff within the ‘blog-item.php’. Can anyone provide guidance?

From the WTI Like Post creator:

1) Option #1: “Try using the function call GetWtiLikePost() just below the excerpt in the template file.” I’m assuming this means that I put “<?php GetWtiLikePost();?>” somewhere. But, I honestly don’t know which .php to add this to.

2) Option #2: If Option #1 doesn’t work, try using the following code:

[Too much code to paste here – please see: http://codex.wordpress.org/Forum_Welcome#Posting_Code%5D