I have been taking piano lessons since I was 5.
I have never played the piano although I am familiar with how one uses a keyboard with keys to cause the hammers to strike the strings and produce sound.
How do the strings make all the different sounds?
The Italian term "piano" refers to the variations in volume produced by the pianist's touch or pressure.
That's interesting I never knew that. When were pianos invented?
Piano
The piano is an acoustic, stringed musical instrument invented in Italy by Bartolomeo Cristofori around the year 1700 (the exact year is uncertain), in which the strings are struck by hammers. It is played using a keyboard, which is a row of keys (small levers) that the performer presses down or strikes with the fingers and thumbs of both hands to cause the hammers to strike the strings. 
The word piano is a shortened form of "pianoforte", the Italian term for the early 1700s versions
the sound itself, with the keys moving up and down, driving hammers that strike the strings. Like its counterpart, a player piano can be played by hand as well. When a scroll is run through the instrument, the movement of its keys produce the illusion that an invisible performer is playing the instrument. Vonnegut uses the player piano as a metaphor to represent how even the most simple of activities, such as teaching oneself how to play the piano in one's spare time, has been replaced by machines instead of