In this code, each letter in the code stands for a different "real" letter.
A stands for Z
B stands for Y
C stands for X
and so on.
To help solve this code, first write out the alphabet, and then write out the alphabet in reverse below it:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
Now, whenever you see an A you look it up in the first alphabet, and translate it into a Z because the Z is directly under the A.
Example:
SCOUT = HXLFG
Here's a code for you to solve:
Z HXLFGH SLMLFI RH GL YV GIFHGVW