A course manager can assign enrolled users into groups manually.

Go to course administration – OpenLearners

In the list of names of enrolled users is a column for ‘groups’. Click on the pencil icon which is ‘edit groups’ for that user and choose the appropriate group from the dropdown list which appears. Forum moderators can have more than one cohort group to moderate, whereas learners will usually only be in one cohort group, the one they were assigned to when they used the enrolment key during enrolment.

It is also possible to add or remove users from a cohort group via the Groups screen (which shows all the members of a group), by clicking on the group and using the ‘add/remove users’ button.