Thank you Rajavenkateshwaran and alchymyth for your responses.
I’m using Buddypress as Childtheme.
I tried to put blogs-loop.php in my child folder but nothing happens.
If I select the own created php-File and add is as template in the Page it’s working and using it noW ??
But Only when I’m leaving Settings > Reading empty under static page > Post page.
But how do I get the an overview of all posts on this site now?
The code I’m currently having in doen’t show anything:
<?php if ( have_posts() ) : ?>
<?php /* Start the Loop */ ?>
<?php while ( have_posts() ) : the_post(); ?>
<?php get_template_part( 'content', get_post_format() ); ?>
<?php endwhile; ?>
<?php twentytwelve_content_nav( 'nav-below' ); ?>
<?php else : ?>
<article id="post-0" class="post no-results not-found">
<?php if ( current_user_can( 'edit_posts' ) ) :
// Show a different message to a logged-in user who can add posts.
?>
<header class="entry-header">
<h1 class="entry-title"><?php _e( 'No posts to display', 'twentytwelve' ); ?></h1>
</header>
<div class="entry-content">
<p><?php printf( __( 'Ready to publish your first post? <a href="%s">Get started here</a>.', 'twentytwelve' ), admin_url( 'post-new.php' ) ); ?></p>
</div><!-- .entry-content -->
<?php else :
// Show the default message to everyone else.
?>
<header class="entry-header">
<h1 class="entry-title"><?php _e( 'Nothing Found', 'twentytwelve' ); ?></h1>
</header>
<div class="entry-content">
<p><?php _e( 'Apologies, but no results were found. Perhaps searching will help find a related post.', 'twentytwelve' ); ?></p>
<?php get_search_form(); ?>
</div><!-- .entry-content -->
<?php endif; // end current_user_can() check ?>
</article><!-- #post-0 -->
<?php endif; // end have_posts() check ?>
Thanks a lot