By default, all pre-installed blogs are displayed using a skin. (More on skins in another post.)
That means, blogs are accessed through ‘index.php‘, which loads default parameters from the database and then passes on the display job to a skin.
Alternatively, if you don’t want to use the default DB parameters and want to, say, force a skin, a category or a specific linkblog, you can create a stub file like the provided ‘a_stub.php‘ and call your blog through this stub instead of index.php .
Finally, if you need to do some very specific customizations to your blog, you may use plain templates instead of skins. In this case, call your blog through a full template, like the provided ‘a_noskin.php‘.
You will find more information in the stub/template files themselves. Open them in a text editor and read the comments in there.
Either way, make sure you go to the blogs admin and set the correct access method for your blog. When using a stub or a template, you must also set its filename in the ‘Stub name’ field. Otherwise, the permalinks will not function properly.