<button onclick="document.getElementById('player').play()"><i class='fa fa-play'></i></button>
<button onclick="document.getElementById('player').pause()"><i class='fa fa-pause'></i></button>
<button onclick="document.getElementById('player').currentTime = 0"><i class='fa fa-stop'></i></button>
<button onclick="document.getElementById('player').volume+=0.1">Громкость +</button>
<button onclick="document.getElementById('player').volume-=0.1">Громкость -</button>