Intermediate level: Drums
Use Smart Drums
The iOS Smart Drums interface is a grid on to which you drag instruments from a selected kit (or tap the dice to randomise everything). Drums positioned at the top are louder; those to the right have more complex patterns.
To keep your pattern, it must be recorded, whereupon it’s converted to editable MIDI data. Note that drums can be moved during recording, for example to make a snare more complex at the end of a bar.
Master the Beat Sequencer
For direct control over beat creation, use Beat Sequencer. This old-school step-based interface enables you to define precisely when drums are triggered, and provides nuance with velocity, note repeat, and ‘chance’ options.
If you need inspiration, tap the Patterns button and select from dozens of built-in presets. Again, there’s a random option if you fancy starting with something more chaotic.
Try live drumming
GarageBand lets you play virtual drums manually. On macOS, select a drum kit and use musical typing or a connected USB piano keyboard to trigger sounds. On iOS, create a Drum track using the Acoustic Drums option.
On iOS, the drums are velocity sensitive, and acoustic kits offer different sounds depending on where the drum is struck. For example, tap the edge of a snare for a rim shot.
Work with Apple’s Drummer
Drummer gets its own section in the iOS Tracks picker, and also exists as a track option on macOS. It’s a smart audio loop creation tool, based on recordings of real drummers.
To start, select a drummer and a style. Then turn on and off individual drums, and fiddle with the pads and sliders to refine what’s played. When happy with your loop, record it. (Drummer loops are rendered audio, note, not MIDI data.)