You're better off doing the following.
Define a regular old Django query for your various kinds of filters. These are very easy to write.
Use the supplied generic view functions. These are very easy to use.
Create your own templates with links to your filters. You'll be building a list links based on the results of a query. For a few hard-coded cases, this is very easy. In the super-general admin-interface case, this is not simple.
Do this first. Get it to work. It won't take long. It's very important to understand Django at this level before diving into the way the admin applications work.
Later -- after you have something running -- you can spend several hours learning how the inner mysteries of the admin interface work.