Query posts by category

query-by-cat.php

<?php
	// Query arguments : https://codex.wordpress.org/Class_Reference/WP_Query
	$args = array(
		'posts_per_page'=> 5,
		'orderby'	=> 'date',
		'order'		=> 'DESC',
    		'category' 	=> 'slider'
	);
	
	// create the query
	$slider = new WP_Query($args);
	
	// loop through the new created query  
	if ( $slider->have_posts() ) :
		while ( $slider->have_posts() ) : $slider->the_post();
			// loop content
		endwhile;
	else: 
		echo __( 'There are no posts to show', 'textdomain' );
	endif;
	
	wp_reset_postdata(); 

?>