SQL 2012 :: Using Symmetric Key Encryption

I am working to set up encryption of my database. am trying to implement a process proposed by the DoD Standard Technical Implementation Guide (STIG) and cannot figure it out. I am using SQL 2012 and the requirement is to

A: Run the following to create a certificate:
USE <'database name'>
CREATE CERTIFICATE <'certificate name'>
ENCRYPTION BY PASSWORD = '<'password'>'
FROM FILE = <'path/file_name'>
WITH SUBJECT = 'name of person creating key',
EXPIRY_DATE = '<'expiration date: yyyymmdd'>'

This script did not work – I did not know what file it was referencing and it kept erroring out, so I used my own process as follows

USE master
GO
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'mY_P@$$w0rd'
CREATE CERTIFICATE certificate_name
WITH SUBJECT = 'Certificate for my database'

[code]....

This also error out, but my questions are the following:

-What would the symmetric key be encrypting?
-The application that is using the database is IIS, so would there be a problem with it communicating with the database?
-Does the key need to be installed on that IIS server?
-Do I need to apply the encryption to the database, column or table.