Open your GarageBand software program. This can be accomplished by moving your mouse cursor over the dock on your Mac's desktop and clicking on the GarageBand icon (an electric guitar). If the icon is not in the dock, select Finder from the dock, open Applications, and select GarageBand.
Select Create New Music Project when the GarageBand window appears on the screen.
Name the project when the prompt appears on the screen. For instance, type the song title in the Save As field.
Select where you wish to save the session in the Where field. You may decide to save the session to your hard drive, or to an external drive you may be using.
Select a tempo, time signature, and key if necessary. These are optional selections that can be made at any time during the recording process.
Click Create.