WAMP: attauching stylesheet to a web page on wordpress

the chrome dev tools – output from the conlost
I’m a newbee to wordpress and I’m trying to attauch to a theme main stylesheet but, I have problems, the styles rules aren’t applied to the page. here is my index.php file so far:

<?php
    get_header();
    if (have_posts()):
        while (have_posts()):
            the_post();
        the_title();
        the_excerpt();
        the_author();
        endwhile;
    endif;
    get_sidebar();
    get_footer();

?>
here is my functions.php file, that I use for uploading the stylesheet:

<?php
function add_theme_scripts() {
    wp_enqueue_style( 'main', get_stylesheet_uri(), false );
}
add_action("wp_enqueue_scripts", "add_theme_scripts");
?>

And however I have tried to upload styles through blogifno in the head of the header file, but it doesn’t work either, the page is shown not styled at all What is the matter? The css file is located in the root folder wihout any subfolders