Apple GarageBand is a complete DAW software included in Mac OSX, which makes it great for beginners and amateurs, since it is free and it also includes several online music lessons. When you start, you can either pick a ready template, or just start with a new empty project.
Its direct workspace is made of several tracks, each welcoming audio samples or MIDI over the timeline. Despite being completely free, GarageBand is indeed a complete DAW, able to realize your own compositions with a Piano Roll, to apply audio filters with the Equalizer, and adjust the sound output by editing the Synthesizers properties or applying any compression.
GarageBand is the best free alternative in case you want to create your own Audio Tracks also in a professional way.