How did they do that?

What about cleaning the outside of the windows? If it is an office block they may well use one of those cradles to do the outside but what if they are flats- maybe they all have tilt and turn windows now.
Our windows here open inwards - the shutters outwards - but the last ones we had in UK had a fixed bottom half and the top half opened - it was a four storey I house and workmen are not allowed to go more than two floors without scaffolding! The top floor was OK as Velux and could be done from inside but our bedroom and the bathroom were a real devil as my arms were not really long enough to cope with reaching the far edges.

Surprised they were allowed to put one up - when we had our apartment there were strict rules about no satellite dishes. It was probably put up by a very brave/foolhardy erector