Sort a 2d array by three columns

I do not understand the way to sort a multi-dimensional array in php. I have a structure like this:

Array (
   [0] (
      ['vname'] => "Bernt"
      ['nname'] => "Mayer"
      ['kl_name'] => "ZR4"
   )
   [1] (
      ['vname'] => "Albert"
      ['nname'] => "Mayer"
      ['kl_name'] => "TR4"
   )
)

My goal is now to first sort by kl_name, and then by nname and then vname. Most important is kl_name.

First I tought I should make objects and store them in the array, but I think sorting them is even more complex. php.net has a nice article about array_multisort, but year, I don't understand it.

You'll want to sort the array with a user defined function (with usort).

You can then manually specify how you'd like the items to be ordered using the kl_name, nname and vname attributes.

Something like this:

usort($arr, function($a, $b) {
    if ($a['kl_name'] !== $b['kl_name']) {
        return strcmp($a['kl_name'], $b['kl_name']);
    } else if ($a['nname'] !== $b['nname']) {
        return strcmp($a['nname'], $b['nname']);
    } else {
        return strcmp($a['vname'], $b['vname']);
    }
});

The function will first attempt to sort by kl_name, then by nname and finally by vname if all previous values are equal.