Selecting Software InstrumentsYou can play a variety of instruments in your GarageBand project by first adding a new track and then selecting your sound from the instrument library.
Add a Track
Start off by adding a new track to the music project. Do this by clicking the Add Trackbutton in the bottom left corner.
This will open a new window that allows you to select one of three instrument options. Click on Software Instrument and then click Create.
A new instrument track will appear on your music project. The default instrument is Grand Piano, but you can change it if you want.
If you have a MIDI keyboard controller connected to your computer, you can begin playing it right away. GarageBand will automatically read a controller when you connect the USB. The signal should appear on the track when you play the instrument.
Find a Software Instrument in the Library
If you want to select a different software instrument, you can choose one from the instrument library. You can access the instrument library two ways: One way to access the library is by double clicking on the track. This will automatically open and close the right sidebar.
Another way to access the library is by clicking the "i" button in the bottom right corner. This will also open and close the right sidebar.
Play the Instrument
Select an instrument from the categories and subcategories in the sidebar. When you select one, you can preview it by playing your MIDI controller while it's selected. When you find an instrument you want to use, select it for the track.