A set is a folder in the learning plan that contains learning assets. Although the assets within it may have a due date, the set itself does not. A set can have subsets (which are more refined groupings within a set) but only two levels of subsets are allowed.
You can create sets on the Personal Learning tab in your learning plan
To create a set
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until the new set is directly below the name of the set to which you want to add it as a subset.
. The new set becomes a subset.