You can find various arrangements of this song online, ranging from basic lead sheets to professional classical arrangements. Classical & Fingerstyle Arrangements
While I cannot directly provide a copyrighted PDF file, you can find high-quality, free legal arrangements on these reputable platforms:
Whether you find a free PDF or purchase a book, here is how to approach the piece technically.
Provides a clean score by Carlos Almarán. Access Classical Guitar Library PDF História De Un Amor by Carlos Eleta Almarán sheet music