Where can I extend the course?

Go to the Users tab and click the black dot in the learner row to go to the learner settings.

How can I extend the course?

Click the button with the date and check 'Alternative end date learner' if you want to give this learner a different end date. Click Update to save.

When you can't extend a course this may be because the learner hasn't started yet. If you click the name of the course and then go to the tab 'Learners', a subscription has the status of either New or Active. When a learner starts their course it changes to Active. You can also manually activate it, by clicking Activate.