Explanation

Scenario:

You must implement auditing for all objects in the ADVSchema schema.
Box 1: CREATE SERVER AUDIT
Create the server audit.
Box 2: ALTER SERVER AUDIT
Enable the server audit.
Box 3: CREATE DATABASE AUDIT
Create the database audit specification.
Box 4: FOR SERVER AUDIT
Example: The following example creates a server audit called Payrole_Security_Audit and then a database audit specification called Payrole_Security_Audit that audits SELECT and INSERT statements by the dbo user, for the HumanResources.EmployeePayHistory table in the AdventureWorks2012 database.
USE master ;
GO
-- Create the server audit.
CREATE SERVER AUDIT Payrole_Security_Audit
TO FILE ( FILEPATH =
'C:\Program Files\Microsoft SQL Server\MSSQL13.MSSQLSERVER\MSSQL\DATA' ) ; GO
-- Enable the server audit.
ALTER SERVER AUDIT Payrole_Security_Audit
WITH (STATE = ON) ;
GO
-- Move to the target database.
USE AdventureWorks2012 ;
GO
-- Create the database audit specification.
CREATE DATABASE AUDIT SPECIFICATION Audit_Pay_Tables
FOR SERVER AUDIT Payrole_Security_Audit
ADD (SELECT , INSERT
ON HumanResources.EmployeePayHistory BY dbo )
WITH (STATE = ON) ;
GO
References:
https://docs.microsoft.com/en-us/sql/t-sql/statements/create-database-audit-specification-transact-sql?view=sql-s