This kind of activity is meant to allow students join empty groups previously created by you.
- Turn editing on the classroom.
- Click on Add an activity or resource button at the desired section or week.
- Select the Group self-selection activity and then click on the Add button.
- Fill the Name and Description fields. In Select groups from grouping, you have to select the previously created grouping. In the Max members per group field, set the corresponding value and select the dates in which the students will be able to join the group.
- To finish, click on the Save and return to course button. The activity will be created and ready for students to join. The instructions students must follow to join the group are the following: How do I join a group.