In this article there will be a step by step of how tagging works, as well as a video to show how its done. 

1.) Find the title in which you want to add tags to. 

2.) Click on the title, it'll bring you to the course details page. 

3.) There you will see a line that allows for you to add tags. 

This will allow for a user to be able to find courses under these specific tags as well as, allow the owner to organize the library based on the different tags.