You don't want to use the publish option.
In the VS menu there should be 'Project', under which should be 'YOURPROJECT Properties...'; Clicking this will open the properties
On the application tab, Fill in the 'Assembly name' with what you want your assembly to be. Most often I find that the namespace the project is in to be a good one, but that's dependent on your namespace naming practices.
Next is the 'Build' tab - On here you select a configuration and can specify various things for it; regarding the DLL that is created, There is an 'Output Path' towards the bottom of this section, which should have something like "Bin\Debug". This is where (in relation to your proj file) the DLL will be placed when you do a "Build->Build MYPROJECT" (or any other way to build the project).
Navigate to that location and you should find a DLL with the name you specified in the Application tab.
This all, of course, depends on using WAP and not WSP. (Oh acronyms, how I love to look up what you are). (WSP doesn't create a DLL)
Then you will place your *.dnn file with all the files needed into a zip file and you will be good to start debugging what's not quite right in the dnn file. :-P Actually, if the module is working on your test site - I think there is a way to generate the manifest file for it, never done that, but I think it exists...
Hope that helps