Step1:Goto below link to download AdventureWorks2012_Database.zip
http://msftdbprodsamples.codeplex.com/releases/view/93587
Step2: Unzip the AdventureWorks2012_Database.zip and it will open up with
"AdventureWorks2014.bak"
Step3: Copy "AdventureWorks2014.bak" backup file and place it in below location
C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\Backup
Step4: Now open SSMS and Restore the backup file with below script
USE [master]
RESTORE DATABASE AdventureWorks2014
FROM disk= 'C:\Program Files\Microsoft SQL
Server\MSSQL12.MSSQLSERVER\MSSQL\Backup\AdventureWorks2014.bak'
WITH MOVE 'AdventureWorks2014_data' TO 'C:\Program Files\Microsoft SQL
Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\AdventureWorks2014.mdf',
MOVE 'AdventureWorks2014_Log' TO 'C:\Program Files\Microsoft SQL
Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\AdventureWorks2014.ldf'
,REPLACE