Amy,
Cohorts and Groups don't have any inherent relation to one another.
A Cohort gets users enrolled in a course, but that's pretty much their only job.
Groups inside a course are independent from the particular enrolment method used to get users into a course. A Group can contain any set of users enrolled in a particular course that you may need for any purpose in the course (https://docs.moodle.org/310/en/Groups).
If you do want to create course Groups from already existing Cohorts, so they automatically match up, you can use the Cohort members to group plugin: https://moodle.org/plugins/enrol_groupsync which should do what you need.
Randy
Cohorts and Groups don't have any inherent relation to one another.
A Cohort gets users enrolled in a course, but that's pretty much their only job.
Groups inside a course are independent from the particular enrolment method used to get users into a course. A Group can contain any set of users enrolled in a particular course that you may need for any purpose in the course (https://docs.moodle.org/310/en/Groups).
If you do want to create course Groups from already existing Cohorts, so they automatically match up, you can use the Cohort members to group plugin: https://moodle.org/plugins/enrol_groupsync which should do what you need.
Randy