Office 365 (Groups) - SharePoint Team Sites in Groups
All Office 365 Groups come with a SharePoint Team site. A SharePoint Team site connects you and your team to the content, information, and apps you rely on every day.
You can use a Team site to store and collaborate on files or to create and manage lists of information.
You can access your team site from the the Site section of your Office 365 Group.
Please see this Microsoft article on SharePoint team sites for more information:
Additionally, you can search the UWM KnowledgeBase for SharePoint related articles.