Once you enter the Interactive Video assignment, you will see a a preview of the video you are going to have to watch. Depending on the assignment, you may also see a box containing instructions from your teacher above that. Read the instructions carefully, and then click "Start Watching" to open the video viewer. 

Once you've entered the video viewer, there are a few things to watch out for. Some very basic options are found on the top and bottom of the video player. 

These icons in the screenshot below, from left to right, allow you to return to a minimised, LMS view (Unfocus); go to the original video link (View Original), mark the assignment as complete (Done); upvote the video as useful (thumbs up symbol) and see the notifications of the assignment (bell symbol).

At the bottom, next to the timer, you have settings for the subtitles (document symbol) volume (speaker symbol) and for video speed (cog symbol).

Questions
Questions, both open and multiple choice, can be added by your teacher, and sometimes these will block you from viewing the video further until they are answered (see the screenshot below with a 'Required' question). Questions can also be added by you or fellow classmates if the teacher allows it during setup by clicking on the plus button in the video progress bar.

Here is a multiple choice question just at the start of the video, which must be answered before further viewing. On the progress bar on the bottom, you can see questions marked in advance. All of the ones represented by padlocks will have to be answered before further viewing, while the one represented with a dot can be answered at any time.

Once you answer a question, the correct answer may be revealed. You can also check this later in the video by clicking on the question in the progress bar or the menu on the left. 

You may also get open questions, like the one below, in which you will have to enter a text answer. You can either type in your answer and submit it or select "Pass & show answer" to skip the question without giving an answer. If this is a graded assignment, you will also see what percentage of your grade each question has, in this example, it's 35% of the total grade.

As soon as you've answered, the correct answer may be revealed (along with any answers that classmates might have recorded), and you will be asked to estimate whether your answer is wrong, almost correct, or correct. Do this by simply clicking the appropriate option.

Finally, to add your own question, press on the red and white "Plus" sign on the player's progress bar. If it doesn't show, move your cursor towards the bottom of the screen. 

Once you click this, it will give you the option to either create a multiple choice (1) or open (2) practice question, or comment (3) (depending on whether the teacher enabled the option - i.e., this might not be possible in some assignments). Note that only one of the three will appear once you select an option, but here they were cropped into one screenshot for convenience.

Fill in the comment or question text, and then the correct answer (if applicable), and click "Publish" to submit your question. This will then be seen by your fellow students and the teacher. 

The Social & Summary Bar (Right)
As you've perhaps noticed, there is a retractable menu bar on the right of the screen. This can perform several functions, in addition to the ones presented in the previous screenshot. By default, it will show annotations/questions sorted on location (1). You can also sort these on when they were added, number of upvotes or number of comments (2). Additionally, you can use this menu to add comments to or upvote questions (3). Finally, when you click any of the questions in the list or on the bottom of the video player, on the progress bar, they will be brought up in this menu. If you've already answered the question, you will see the option you chose and the correct one (4), and if you've not yet answered, you will get the option to chose an answer and submit it (5).

Finally, if you pick your own contribution, you will get the option to edit or delete it by clicking the 3 vertically placed points in the upper right corner.

Tracking your progress.

In the bar at the top of the assignment you can see an overview of how much of the assignment you have completed and how many elements you can still complete in order to receive a full grade.

Clicking on the progress icons you can find how many discussions and questions are still available for you to join in order to receive a grade.