If you think the brass family got its name from being made of brass then your right. But they have not always been made just from brass, it has been known that they have been made from wood, horns, shells, animal hide, and with the rise in technology they have also been made from plastic, nickel, gold, and silver. But no matter what they are made of there still played the same.
Just like the woodwind family brass players use their breath to produce sound, but instead of blowing on a wooden read brass players buzz their own lip on a metal cup shaped mouthpiece of varying sizes. These sizes are determined by the instrument and the players preferences. The trumpets mouthpiece is about as big as a quarter, the trombones mouthpiece is about the width of a golf ball, and the tuba has the biggest mouthpiece of them all, its about 2 inches wide and it feels like its eating your face. The mouthpiece helps amplify the buzzing to create the varying sounds.
Most all brass instruments have valves that that are connected to the many feet of pipe. These valves control how much pipe is being used to play a note, if there are more valves being pressed there is more pipe that the sound has to go through, this will generally make a lower sound. The only brass instrument to not have valves is the trombone. The trombone, instead of having valves has a slide, it makes different sounds by extending or shorting its slide. this makes it the only instrument to play all the notes with a single action.