O you could look in the E-Books section for
The Mysterious Affair at Styles and download it already properly formatted for the 500/505.
https://www.mobileread.com/forums/showthread.php?t=11430
Actually, for text there is no way to add metadata to it. But if you were to convert it to LRF using Librps500 or Book Designer or to RTF you could have proper metadata.