Remove the Next and Previous post section?

Edit single.php ( /wp-content/wptouch-data/themes/bauhaus(alternatively your child theme name)/default/single.php ) line55
from
<?php get_template_part( 'nav-bar' ); ?>
to
<?php /* get_template_part( 'nav-bar' ); */ ?>

Alternatively you can also just delete that line.

Just in case you don’t know already:
Create a copy of the theme first, before you edit anything, otherwise your changes get overwritten with the next update.
They call it child “creating a child theme” but basically it’s just a copy (not really a child theme like in regular WP themes)

Creating child themes: https://support.wptouch.com/support/solutions/articles/5000523469-themes#newthemes