Help with Custom Post Types

I need some help with Custom Post Types.
The theme I am trying to use has 4 hard coded custom post types already and I need to add another. I successfully created the post type with a plugin but there is no detailed instruction available that would show how to create a page that would display the new post type content.(Not for a Newbie anyways)
Basically I want to create a “Groups” post type. and have 1 page to display all the groups and another to display the groups individually in a similar fashion to the way it displays the “Staff” post types that is already hard coded in the theme.
I know this should be pretty basic with the plugins and other tools available, but I am stuck. I know it may be a little more complicated because the theme has a few custom page templates already, but I am pretty sure it shouldn’t be too complicated.
Please Help.