First, head over to your Lessons module by clicking Lessons
Hover your cursor over the lesson you wish to take and click it
If your teacher has specified that the activities must be completed in order, all activities after the first one will be greyed out. To begin an activity, click on the tile.
Depending on the activity type, you may have to download a file, play a video, or read text provided in the tile. Once you've finished, check the box next to Mark Completed. That activity will now show up to you and your teacher as completed.
Continue for each activity. When you're finished, click Save & Exit in the top right corner of the screen.