【Library】 If I've already downloaded a course, will viewing it use up data?

Step 1: Tap [Download] to download the course.

Step 2: Tap [Downloaded].

Step 3: Tap [Study].

Step 4: Study the course.

 Note: The first three steps will use up data (including the third step to start studying). The fourth step, studying the already downloaded course, will not use any data.