A score is a representation of sounds using visual symbols. Learning to read and write music is no different from learning to read and write a foreign language.
Music notation is a sonic blueprint, like this blueprint that tells a shipbuilder how to build a ship:
Or you can think of it as a sonic roadmap, like this visual map of the SUNY-Broome campus. The symbols of music notation — lines, bars, staves, notepads — tell you in what direction to go, how far, and how fast.
Some unusual scores
A heart-shaped score by 15th-century French composer Baude Cordier:
Makrokosmos Book I: The Magic Circle of Infinity by George Crumb (1972)
Aria by John Cage (1957)
Which can sound like this (it is a sort of guided improvisation):
Helicopter String Quartet by Karlheinz Stockhausen (1995)
It sounds like this:
Here are two examples of scores by American composer and jazz player Anthony Braxton: