When you create a group, we set a default sharing window of Monday - Friday, 8am to 8pm.
You can easily change the times at which the group is available.
To do so, select Group Avalability from the top right drop down menu.
On the Group page, select the group you wish to change.
In a section titled Time Range, check the days you wish to share. Edit the time of day if necessary and click Save.
The Time Range options set for a group denote the maximum time range shared with the audience. If a group member sets a more restrictive time range for their account, their availability will be clipped.