Sampling is a music production method in which parts of an existing song are copied, adjusted and repurposed to make a new piece of music. Sampling is one of the many ways in which rap artists create the beats to their songs, and many other artists use the occasional sample to accent a piece. You can sample in Garage Band by importing audio and adjusting it using the Garage Band interface.
Locate the song you wish to sample on your hard drive. Open a "Find" window and navigate to the file location.
Click on and launch the Garage Band program and start a new project by clicking "New Music Project" on the prompt that appears on-screen.
Click back into the "Find" window that contains your sample song. Click on and drag the song into Garage Band's track area. The song is imported in its entirety.
Use Garage Band's built-in controls to sample the song. Click and drag the right end of the song to set the end of the sample clip. Drag the left end to set the beginning of the sample clip. When finished, you should have a small piece of your song with just the desired sample portion inside.
Press the "Command" and "C" keys simultaneously to select the slice of song you have just created and copy it . Press "Command" and "V" to paste it. Your small sample is duplicated and pasted exactly where the first slice ends. Repeat this process a few more times to create a sample loop.
Garage Band imports MP3, AIF, AAC and WAV files.