Material.js

var d = $;var x = $('.c-box-list.c-box-list--linked.c-video-player__lesson-list.c-video-player__lesson-list--open').children
for(var i = 0;i<x.length; i++) {
    var z = x[i];
    (function() {
        var y = z.children[0];
        setTimeout(function() {
            console.log('Switching to ' + y);
            y.click();
            
            setTimeout(function() {
                d('a.o-button--green.o-button--files').click()
            }, 5000)
        }, i*10000)
    })();
}