How to use my own video and be able to play from a specific time?
May be you can try with javascript

document.getElementById('YOURVIDEOID').addEventListener('loadedmetadata', function() {
  this.currentTime = 50;
}, false);


In jquery

var vid = $("#video")[0];
$("#button").click(function(){
    skipTime(100);
});

function skipTime(time) {
    vid.play();
    vid.pause();
    vid.currentTime = time;
    vid.play();
};