private void addPanelsToContentPane() {
        // Default Page user sees, the Login Page.
        contentPane.add(MainPanel, "Login Page");

        // Page User sees if they are Staff after logging in.
        adminPage = new AdminPage(contentPane);
        JScrollPane scrollAdminPage = new JScrollPane(adminPage.getAdminPagePanel());
        contentPane.add(scrollAdminPage, "Admin Page");

        // Page User sees after logging in.
        userPage = new UserPage(contentPane, hospital, adminPage);
        JScrollPane scrollUserPage = new JScrollPane(userPage.getUserPagePanel());
        contentPane.add(scrollUserPage, "User Page");

        // Page User sees when signing up.
        NewUserPage newUserPage = new NewUserPage(contentPane, hospital);
        JScrollPane scrollNewUserPage = new JScrollPane(newUserPage.getNewUserPagePanel()); // NewUserPage requires scrolling.
        contentPane.add(scrollNewUserPage, "New User Page");

        // Page User sees when clicking on the View Surgery button in the Surgery Page.
        ScheduleSurgery scheduleSurgery = new ScheduleSurgery(contentPane, hospital);
        JScrollPane scrollScheduleSurgery = new JScrollPane(scheduleSurgery.getScheduleSurgeryPanel());
        contentPane.add(scrollScheduleSurgery, "Schedule Surgery Page");
    }