r_honey,
Below is a sample (empty) DNN module manifest file. I borrowed it from the training materials for my Module Development Course.
Typically this will be in the root of your module's project and be named after your module's name (e.g. EngagePublish.dnn)
<dotnetnuke version="3.0" type="Module">
<folders>
<folder>
<name></name>
<friendlyname></friendlyname>
<foldername></foldername>
<modulename></modulename>
<description></description>
<version></version>
<resourcefile></resourcefile>
<dependencies></dependencies>
<modules>
<module>
<friendlyname></friendlyname>
<cachetime></cachetime>
<controls>
<control>
<src></src>
<type></type>
<helpurl></helpurl>
</control>
<control>
<key></key>
<title></title>
<src></src>
<type></type>
<helpurl></helpurl>
</control>
<control>
<key></key>
<title></title>
<src></src>
<type></type>
<helpurl></helpurl>
</control>
</controls>
</module>
</modules>
<files>
<file>
<path></path>
<name></name>
</file>
</files>
</folder>
</folders>
</dotnetnuke>
Hopefully just seeing this helps clear up some of your questions!
This can either be imported into DNN or bundled with your module files in an archive (zip) and be installed. Both of these options are available from the module registration page (Host -> Module Definitions).
Also a tip on how I generally use this file when bundling with an installable module package -- the <resourcefile> element will contain the name of a zip file. Inside of this zip file will be all of the module "accessories" such as images, flash, javascript, css, user controls, etc... These files will be unzipped into the module's directory upon installation. Effectively you end up with a resources.zip inside of your module package (zip within a zip).
But for the elements of the module that DNN needs to know about when you register the module -- i'll use the <files> section (e.g. assemblies and SqlDataProvider files).
This cuts down on the amount of maintenance you have to do in your DNN file when adding or removing pieces of content in your module.
Hope that helps!
Take care,
Ian