Semi new to this got a question about metadata

When I am in the media player for atv black 1.5 some things have the correct info some have none at all and just use a frame as the image for the file. While some just have the wrong info all together?  What is the best way to fix this?

It all depends on how the file is named for the metadata that is obtained.

How should I be naming the files?

How are your files named?