These are the characteristics of a team site.  

Many options have been selected to make simplify the management of the site.

A team collaboration site can include multiple tiers or layers to align with team structure.

• Team Group - General membership of the overall team.  
• Leadership Group - subgroup that runs the team. Even if a team has a single leader, the group makes it easy to share or hand-off responsibilities in the future.

Permissions control access to areas of a team site:

• Public pages - Home, About and similar (visible to the public or perhaps restricted to the team's organization)
• Team Private - accessible only to Team Group members
• Leads Private - accessible only to Leadership Group members
• etc.

View example:  demo.steveraab.com

Permissions (Sharing) settings do not require changes during normal operations. Team sites utilize Google Sites 'Page-level Permissions' functionality to assign varying, customized permissions. Permissions were configured when the site was created and are granted to Google Groups which contain the individual members. Therefore, there is no need to edit site permissions as team membership evolves over time.  

• Designated team leaders maintain the Google Groups membership lists.

Teams can adjust access to particular pages by rearranging the page in the 'site map' to the area with the desired permissions.

These are the standard team site permission settings:

• Owners - one or more Google Accounts have ownership permissions, the highest permissions.  Refer to Owner Tasks.
• Editors - Leadership Google Group - can view and 'edit' all site page.  Refer to Editor Tasks.
• Viewer - Team Google Group - can view team and public areas of site, but not Leaders Private area.  Can not edit site.

The sidebar is configured with 3 elements: 

• Automatic menu - all site pages appear (restricted by the permissions of the user)
• Unlock private pages - links that open the private areas of the site - for users with sufficient permissions
• Quick Links - a few relevant links to other organization resources

This covers the basics.  Additional sidebar elements can be added by the site owner.

The automatic menu has been selected for ease of use.

This is 'automatic' because it presents all pages that are in the site (site map), restricted by the permissions of the user.

When new pages are added to a site, they automatically appear in the menu.  When pages are rearranged within the site map, they automatically appear in their new location in the menu too.

Automatic updates are a big benefit over manually configured menus (horizontal and/or sidebar) that must be edited by the site owner each time a change occurs.

The foundation elements of the site are configured to accommodate cloning (copying) the site across multiple teams within an organization.

• Header - displays the site name (so banners son't need to be customized)
• Sidebar - includes some useful organization-wide links
• Footer - settings
• Site Look and Feel - preconfigured Theme, customization, Site Layout have been tuned.
• Mobile enabled - site adjusts for mobile access