Are you trying to workout what this it? – localhost/wordpress/wp-admin-
The short answer is dont worry about it if you dont know you dont need it!
If your curious then its simply the adress of the login page for the install you are running on your local computer before you make it live online.
So unless your a developer or or web designer you are not going to have to worry about it.
If you are a designer here are a few great tutorials about it.
Hope that helped.
Here is a video on how to set up your local host.