The directions vary depending on what you're changing, so we don't have it listed out anywhere.
If you're wanting to move the extended description above the Buy Now and Add to Cart buttons, you'll first need to create the following directory in your theme: /exchange/content-product/loops/.
Then you'll go into exchange/lib/templates and copy the content-product.php file. You'll also need to copy the product-info.php file in exchange/lib/templates/content-product/loops/ directory.
In your copy of content-product.php, remove the following lines:
<div class="it-exchange-product-advanced-content"> <?php it_exchange_get_template_part( 'content-product/loops/product-advanced' ); ?> </div>
Save the copy and then upload it to /wp-content/themes/YourTheme/exchange/.
In your copy of product-info.php, add 'extended-description' to the array before 'super widget'. So it'll look like this:
<?php foreach ( it_exchange_get_template_part_elements( 'content_product', 'product_info_loop', array( 'base-price', 'description', 'extended-description', 'super-widget' ) ) as $detail ) : ?>
You'll then upload that file to /wp-content/themes/YourTheme/exchange/content-product/loops/.
Give that a try and let us know if you have any additional questions.