I am assuming that you want to write a prototype of some sort for which you want a sample database to work with. And I am assuming that you don't have AdventureWorks on your machine. Putting down quick set of steps:
"exec sp_attach_db @dbname=N'AdventureWorks', @filename1=N'C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\AdventureWorks_Data.mdf', @filename2=N'C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\AdventureWorks_log.ldf'"
This will attach the AdventureWorks database. Fire up SQL Server Management Studio and confirm whether Adventure Works exists or not.