Advanced Functionality

Hello,

I looking for help to implement some functionality, but don’t have the WordPress dev knowledge to pull it off. The details are below:

1. Have a drop down menu which contains months where there are posts available, sort of like an archive thing. (How would I populate this?!)
2. When the user selects a month from the drop-down, this month with be used as a parameter in the url. I.E https://www.mydomain.com/pages/folio/?filter=September

(This step I can do myself).

3. Then, if the filter parameter is set, I want the code below (which i currently have fetching my posts) to be modified to only fetch posts from that month (which will be the value of the $_GET[‘filter’]

Code I currently have fetching posts:

<?php
	$taxonomy = 'category';
	$param_type = 'category__in';
	$term_args=array(
		'include'=> '3',
		'orderby' => 'name',
		'order' => 'ASC'
	);
	$terms = get_terms($taxonomy,$term_args);
	if ($terms) {
		foreach( $terms as $term ) {
			$args=array(
				"$param_type" => array($term->term_id),
				'post_type' => 'post',
				'post_status' => 'publish',
				'posts_per_page' => 10,
				'caller_get_posts'=> 1
			); 

			$my_query = null;
			$my_query = new WP_Query($args);
			if( $my_query->have_posts() ) {
				$count = 0; ?>

				<li>

					<?php while ($my_query->have_posts()) : $my_query->the_post();
					if ( ++$count > 1 && ($count - 1) % 2 == 0 ) echo '</li><li>' ; ?>

						<!-- Removed irelevant code -->

					<?php endwhile; ?>

				</li>

			<?php }
		}
	}

	wp_reset_query();

?>

Hopefully this isn’t too ambitious, I’ve tried to include as much detail as possible.

Thanks in advance.