This is the 184th most frequent German word.
besonders
"Especially" or "particularly."
Here, 'besonders' is used as an adverb to intensify the adjective 'schön' (beautiful), emphasizing the degree of beauty.
Dieses Gemälde ist besonders schön.
This painting is particularly beautiful.
In this context, 'besonders' functions as an adverb emphasizing the importance of understanding the rules.
Es ist besonders wichtig, die Regeln zu verstehen.
It is especially important to understand the rules.
Here, 'besonders' is used to specify a preference, highlighting autumn among other things appreciated.