Enter the course you want to use Groups in.
Expand the Actions Menu (Gear Icon) in the top-right corner of the page.
Select the Edit Settings option.
Scroll down to and expand the Groups section.
Set Group mode to your choice:
Set Force group mode to No. (This will let you choose what activities are separated into groups)
OPTIONAL: Set Default grouping to the grouping containing all your separate groups if you plan to use the same groups over the entire course.
Scroll to the bottom of the page and click the Save and display button.