I need someone to help me in C# language.

Write a program that decodes secret messages read from a text file using an "alphabetic shift." So, for example, a shift might appear as:

ORIGINAL: ABCDE...XYZ SHIFTED: CDEFG...ZAB

for example, BEER with a shift of 2 would be DGGT.

You must utilize stepwise refinement to break this program into appropriate and less-complicated components, say: 1.) Read the encoded message from the attached MessageIn.txt file, 2.) Count the instances of each character in the file, 3.) The most common character in the message should be an "E". Use this information to calculate the amount of the shift, 4.) Print out the decoded message.