Only thing printing to the browser window is 'undefined'...?

In the for loop you need to be checking i against the length of the students array. Right now it's being checked against the students array itself, which means the for loop is not running even once. Here's how to do it:

for(var i = 0; i < students.length; i++) {
...
}

The reason you're getting the undefined printed at the top of the page is because the message variable is not instantiated as an empty string. This makes the message variable hold some arbitrary information in it and being printed as undefined. So to fix it you just need to instantiate it as an empty string at the beginning like this:

var message = "";

I believe for in loops are meant to be used with objects and the students array is an array of objects. If you use a for in loop with an array, the variable defined in the for loop will hold the index of the array. So to use for in with the students array here, you would need to do it like this:

for (var student in students) {
  message += '<h2>Student:' + students[student].name +'</h2>';
  message += '<p>Track: ' + students[student].track +'</p>'
  message += '<p>Achievements : ' + students[student].achievements +'</p>'
  message += '<p>Points : ' + students[student].points +'</p>'
}

The variable student merely holds the current index value through each iteration of the loop which is exactly what i is doing in a regular for loop.