Downloading music onto a laptop is the same as with any other computer.
Establish an Internet connection and open your web browser.
Go to the site you wish to download music from. Some sites are open to toward all users, such as Amazon.com; others are designed to go with a particular company's portable music player, such as Apple's iTunes and iPod and Microsoft's Zune site and player.
Download and install the multimedia player software program required by that site (i.e. iTunes) if you have not already. Follow the on-screen prompts to install.
Create and open a user account; if you already have one, log on.
Browse the site's music store or search for selections by title, album, artist or genre.
Select the tracks and/or albums you wish to download and follow the prompts to begin downloading. Follow the progress on screen if you wish until the downloads are complete.
Different sites may offer different prices for various selections. Shop around a bit before purchasing music if you'd like; checking the artists' websites and other sites may allow you to save money.