$(document).ready(function() {

  var $steps = $('.step');

  var currentStep = 0,

      nextStep;

  $steps.slice(1).hide(); //hide all but first

  $('#next').on('click', function(e) {

    e.preventDefault();

    nextStep = currentStep + 1;

    if (nextStep == $steps.length) {

      alert("You reached the end");

      return;

    }

    $($steps.get(currentStep)).hide();

    $($steps.get(nextStep)).show();

    currentStep = nextStep;

  });

});