Imagine you have a bunch of toys that make different sounds when you play with them - some sound high and some sound low. Now imagine that instead of toys, we have people who can make those sounds with special instruments called strings.
The string section is a group of these special instruments - violins, violas, cellos, and basses - that play together in an orchestra or band.
When they all play together, they can create beautiful music that makes you feel lots of different emotions. Sometimes their music can be happy and bouncy, and sometimes it can be sad and slow.
Each instrument in the string section has a different job - some play the melody (the main tune you hear in the music), while others play the harmony (extra notes that make the music sound fuller).
So when you hear music that has a string section, you can listen for all the different sounds these special instruments make, and see how they come together to make something really amazing!