Layout template bulk modification

I’m glad to use templates, but didn’t find how to use it. There are layout templates – i can save it and in further use when will create a new page. But i need next modification of the layout on the few similar pages.

Hi!

I create a new template php on the base of page.php just gave a new name. As i understand, this part of code responsable for what i see on the page from avia layout:

<div class='container'>

				<main class='template-page content  <?php avia_layout_class( 'content' ); ?> units' <?php avia_markup_helper(array('context' => 'content','post_type'=>'page'));?>>

                    <?php
                    /* Run the loop to output the posts.
                    * If you want to overload this in a child theme then include a file
                    * called loop-page.php and that will be used instead.
                    */

                    $avia_config['size'] = avia_layout_class( 'main' , false) == 'fullsize' ? 'entry_without_sidebar' : 'entry_with_sidebar';
                    get_template_part( 'includes/loop', 'page' );
                    ?>

				<!--end content-->

Also i have a page with avia contend (title, text, cf etc.) and want to not only create may similar pages but have poissibility to modificate – mean change blocks places, add some blocks and on all smilar pages in the same time. So i need to use template for a page?.

1) Can i create template on the base of existed page and use it? How to add avia tags and blocks to the template?
2)