Reusable Content Collections allow you to reuse the same element in new and existing tutorials added to your academy.
To add a collection to a tutorial click on the tutorial you would like to add a collection to. From here click Add New and then select Reusable content
Here you will see a list of the current collections you have created or added from the marketplace. Click into the collection you are interested in, and then select the element you would like to add.
Once selected the collection will appear as an element in your tutorial. (NOTE: you are only able to make a collection an intro in tutorials you have created.)