You can use this as start theme or as boilerplate for theme
this has all the start up files
https://github.com/d4rkvent/understrap

<?php
 
get_header();
 
if ( have_posts() ) :	while ( have_posts() ) : the_post(); ?>
 
        <article class="post">
            <h2><a href="<?php the_permalink() ?>"><?php the_title() ?></a></h2>	<?php the_content() ?>
        </article>	<?php endwhile;
 
else :	echo '<p>There are no posts!</p>';
 
endif;
 
get_footer();
 
?>

{"tags":[{"tag":"p","content":"wordpress theme development"},{"tag":"textarea","content":"Create style.css and index.php in your custom theme folder\n \nWe now know where WordPress theme files are in the file system. We also have created a new folder named customtheme in our themes folder. We are now going to create two empty files in this directory. One is called index.php and the other is called style.css.\n\nstyle.css\nWordPress actually reads the comments that you place in the style.css file. This is where you specify specific information about the theme you are building.\n\nThe style.css is a stylesheet (CSS) file required for every WordPress theme. It controls the presentation (visual design and layout) of the website pages.\n\nIn our snippet here we simply assign a Theme Name, the Author, the Author URI, and the Version number of our theme.\n\n\/*\nTheme Name: customtheme\nAuthor: Vegibit\nAuthor URI: https:\/\/vegibit.com\nVersion: 1.0\n *\/\n \nindex.php\nIn this file, we just want to output something to the screen to prove that our custom theme is working.\n\n<h1>Custom Theme!<\/h1>\nMarkup\nGreat Job! Believe it or not, you have created your first WordPress Theme.","code_language":"php"}]}