What is the difference between Home and Groups?
Home is the starting page on which you land immediately after login. This is the meeting point for everyone within your environment. This page combines general information that is relevant to everybody with private information. Recent changes, for instance, are private: you will see only the changes from the groups to which you have access.
You can click to your groups from Home, e.g. to your project or expert group.
A group is a meeting point for a specific target group; for instance, to work together on a project or to exchange expertise on a specific topic. A group can be private or public. A public group is accessible to every member. A private group requires explicit access authorisation.