On his return Miller brought some association football equipment and a rules book with him. He then went on to develop the new rules of the game amongst the community in São Paulo. In 1888, six years before his return, the first sports club was founded in the city, São Paulo Athletic Club.
In this quote they are talking about how miller brought some a association football equipment and a rules book with him. To develop the new rules of the game.
This is important because so that people can know the rules of the sport while playing soccer also so nobody will get hurt.
This connect to me because I had a rule book like that which I used to read so that I can know my rules with my friends.