php grabbing every post made?

Based on WordPress template hierarchy, categories are displayed using the category.php template. So in other to display your preferred category, you’ll need to create a category.php file, and use the query below:

$cat_query = new WP_Query(
    array(
        'post_type'         =>  'post',
        'cat'               =>  $cat, //WordPress global for getting the current category
        'posts_per_page'    =>  5,
        )
    );

And then you loop like so:

if( $cat_query->have_posts() ) : while( $cat_query->have_posts() ): $cat_query->the_post();