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Course level - The group mode defined at the course level is the default mode for all activities defined within that course. To use groups you need first to set a group mode in Administration > Course administration > Edit settings.
Activity level - Each activity that supports groups can also have its own group mode defined. If the course setting "Force group mode" is set to "Yes" then the option to define the group mode for individual activities is not available. If it is set to "No", then the teacher may change the group mode.
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Login to Moodle course
Select Participants from Course navigation
Select Groups from the dropdown menu
Add a group name and optional description
Select group visibility
Click the 'Save changes' button
Select the group to which you want to add participants, then click the 'Add/remove users button
In the "Potential members" list, select the users you want to add to the group. Multiple users may be selected using the Crtl key.
Click the Add button to add the users to the group
View
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groups in Moodle gradebook
Navigate to the gradebook by selecting the Grades tab
Click [Grader report] from the far left dropdown menu (if it is not already selected)
Within the dropdown menu labeled Select separate groups or Select visible Groups (depending on your selection above), you can choose to display a single group’s grades, or grades for all students or select All Participants