Attaching database SQL 2005 question

Hello,
I am a student. I am naive in the computer world as well as software section. Now a days I am studying Microsoft SQL server. I am using Microsoft SQL server 2005 edition. I have a database mdf file and log file. I need to attach those files again in the database. As my SQL server is new, this database is not there. But I don’t know exactly how to attach a database.
Can anyone tell me?
Help me please.
