First a word of caution:
rmcommon is in alfa and should NOT be used in a production site. This tutorial is just for testing.
With that said, let's get to the tutorial.
There are 2 parts; one goes into your php file and another into your smarty template. Let's start with the php part.
PHPopen the index.php file of your module and insert this code:
 //get all comments for this article/item 
    RMFunctions::get_comments('tutorial','post='.$post); 
    // Comments form 
    RMFunctions::comments_form('tutorial', 'post='.$post, 'module', '');  
The first line gets all comments for this item. It's a function that needs 2 vars:
'tutorial' -> this is the name of your module
'post='.$post -> this is the ID of the item. Look at the url for your module. you will probably have something like this:
 http://mysite/modules/myModule/index.php?mid=8  
In this case you could write your comment code as this:
 //get all comments for this article/item 
    RMFunctions::get_comments('myModule','post='.$_GET['mid']); 
    // Comments form 
    RMFunctions::comments_form('myModule', 'post='.$_GET['mid'], 'module', '');  
Mind you this isn't the original code from mywords. If you want to further study this, here it is:
 // Comments 
// When use the common utilities comments system you can choose between 
// use of Common Utilities templates or use your own templates 
// We will use MyWords included templates 
if ($post->getVar('comstatus')){ 
    RMFunctions::get_comments('mywords','post='.$post->id()); 
    // Comments form 
    RMFunctions::comments_form('mywords', 'post='.$post->id(), 'module', MW_PATH.'/class/mywordscontroller.php'); 
}  
SMARTYNow the smarty part. Open your smarty template and place this code at the bottom:
  
<a name="comments">a> 
<{include file="db:rmc_comments_display.html"}> 
<{include file="db:rmc_comments_form.html"}> 
  
That's it! Simple don't you think?