[MarkPW]

and insert my custom php code in that box on that screen, and toggle the drop down to the location I want....and that is it??

Yes, that's it. When you add a plugin, I recommend you look through the vb files to ensure you have chosen the appropriate (hook) location to execute your code.

Do I need to add a product or anything like that?

No, you can add it to the default (vBulletin).

No chance you could just walk me through a very simple one from start to finish...

I didn't quite interpret what you were asking, but since this topic was about saving info to a seperate table upon registration, I'll show you how to do that.

Basically, you would "Add New Plugin" -> choose "vbulletin" as product -> Select the hook location of either "register_addmember_complete" (to execute your code upon a successful registration), or "register_activate_process" to execute upon a successful e-mail validation (I personally prefer this to keep my seperate table clean of any unvalidated users) -> enter a name for your plugin -> and add your code. Example (using vB's database class):

PHP Code:

$db->query("INSERT INTO your_table SET userid='".$userinfo['userid']."'");