How does one unlock a "locked" file?

[norcalstadium]

so i'm trying to remove some music from my computer (because i have duplicates of the same song), and my macbook pro is preventing me from doing so... please help!

 

[J@ffa]

Click once on the file, hit Command - I (the command key is the one with an Apple logo on it to the left of the spacebar), and there'll be a checkbox next to the word 'Locked' — untick it.