hero theme boxes

Hello I am new to coding and I have figured out how to change the boxes on the front page to show 6 boxes instead of 3. I need to have 3 columns and 2 rows and if I change the code in front-page.php from 3 to 6 it just lines up 2 columns??? What am I missing? Any help will be better that fishing in the dark with no pole.

here is the code I changed

<!--boxes-->
		<div id="box_container">

		<?php for ($i = 1; $i <= 3; $i++) { ?>

				<div class="boxes one_third <?php if ($i == 3) {echo "last";} ?>">
						<div class="box-head">

And I just changed it to this

<!--boxes-->
		<div id="box_container">

		<?php for ($i = 1; $i <= 6; $i++) { ?>

				<div class="boxes one_third <?php if ($i == 6) {echo "last";} ?>">
						<div class="box-head">

Thanks in advance
The website