How do I build a WordPress Profile/Author Header?

A quick way to find your way is by installing the ACF plugin with these rules:

And create author.php file with this code:

<?php while ( have_posts() ) : the_post(); ?>

    <?php // get the background_picture ?>
    <?php $background_picture = get_field( 'background_picture', 'user_'.get_the_ID() ); ?>
    <img src="https://wordpress.stackexchange.com/questions/272675/<?php echo $background_picture["url'] ?>" alt="">

    <?php // get the profile_picture ?>
    <?php $profile_picture = get_field( 'profile_picture', 'user_'.get_the_ID() ); ?>
    <img src="<?php echo $profile_picture['url'] ?>" alt="">

    <?php // get the bio ?>
    <?php echo get_the_author_meta( 'description' ) ?>

<?php endwhile ?>