Wish I could say yes to your questions. But there is none.
You can search here for specific template files and get some results.
But in a nut shell the TPL files are the guts of the forum.
For instance the header.tpl file has things such as the default header which includes the menu items portal page,forum list,mystuff etc.
Here is one post that adds a menu item .
Just remember that editing those files is considered a modification to the stock code and is not really supported here. If you break your board you may need to retore your original files.
