Sorting songs

I have a small issue here: I imported some albums and songs from my computer to my songs and some were sorted correctly (the albums were sorted under the correct artist etc) but some weren't.

Some were directed to "unknown artist" and this makes the entire media library a huge mess. Is there any way to redirect these songs into their respective artists/bands?

Example: I have a song called "Gate Openerz" by "DJ Sharpnel" and the song is included in their album "Cyclick".

So, logically, the song should be sorted like this:

DJ Sharpnel > Cyclick > Gate Openerz

But it's instead sorted like this:

Unknown artist > Gate Openerz

Also, is there any way of changing the genre? The song is included in the wrong genre as well on Cloudskipper

 

The iTag app made a difference, and I can now organize my media library without any issues. Thank you very much