Hi William,

The position is defined in the following blocks: mainbody-content-left.php, mainbody-content-right.php, one-sidebar-left-with-mastcol.php and one-sidebar-right-with-mastcol.php. By default, those blocks are not used, you can load the blocks to the layout you want to use and you will get the mast_col position in the layout.

Here is a sample block:

<div id="t3-mainbody" class="container t3-mainbody">

	<div class="row">



		<!-- MAIN CONTENT -->

		<div id="t3-content" class="t3-content col-xs-12 col-sm-8 col-sm-push-4 col-md-9 col-md-push-3">

			<?php if($this->hasMessage()) : ?>

			<jdoc:include type="message" />

			<?php endif ?>

			<jdoc:include type="component" />

		</div>

		<!-- //MAIN CONTENT -->



		<div class="t3-sidebar t3-sidebar-left col-xs-12 col-sm-4 col-sm-pull-8 col-md-3 col-md-pull-9">

			<div class="row">



				<!-- MASSCOL 1 -->

				<?php if ($vars['mastcol']) : ?>

					<div class="t3-mastcol t3-mastcol-1 <?php $this->_c($vars['mastcol']) ?>">

						<jdoc:include type="modules" name="<?php $this->_p($vars['mastcol']) ?>" style="T3Xhtml" />

					</div>

				<?php endif ?>

				<!-- //MASSCOL 1 -->



				<!-- SIDEBAR LEFT -->

				<?php if ($vars['sidebar']) : ?>

				<div class="t3-sidebar col-xs-12 <?php $this->_c($vars['sidebar']) ?>">

					<jdoc:include type="modules" name="<?php $this->_p($vars['sidebar']) ?>" style="T3Xhtml" />

				</div>

				<?php endif ?>

				<!-- //SIDEBAR LEFT -->

			</div>

		</div>



	</div>

</div> 

Gardner.