The first part (about 15 minutes long) mainly focuses on his official role as the Hereditary Grand Duke; it shows footage of his recent trip to China, him taking part in a meeting of the Council of State, and many other activities. It also offers an insight into the work he does behind palaces doors. You can also see him playing tennis and walking through beautiful Luxembourg. One of the biggest treasures, in my humble opinion, is the footage of Guillaume throughout the years; starting with him as a baby, as toddler, attending school, playing in the gardens of the Château de Fischbach but also attending Sandhurst.
The second part that will be broadcasted tomorrow, will focus more on Guillaume's private life. There is a small preview available in which he, among other things, talks about his girlfriend.