You can find some code samples for using hooks in the extension User Locations

um_member_directory_disable_clustering.php

<?php

/**
 * Disable Clustering
 * You may add this code to the file functions.php in the active theme directory.
 *
 * @author Ultimate Member support <support@ultimatemember.com>
 * @link   https://ultimatemember.com/extensions/user-locations/
 */
add_action( 'wp_footer', function () {
	if ( function_exists( 'UM' ) ) {
		?><script type="text/javascript">
			wp.hooks.addFilter( 'um_member_directory_disable_clustering', 'um_user_locations', function ( disableClustering, directory ) {
				disableClustering = true;
				return disableClustering;
			}, 20 );
		</script><?php
	}
}, 20 );

um_user_locations_marker_data.php

<?php

/**
 * Change the map marker title
 * You may add this code to the file functions.php in the active theme directory.
 *
 * @author Ultimate Member support <support@ultimatemember.com>
 * @link   https://ultimatemember.com/extensions/user-locations/
 */
add_action( 'wp_footer', function () {
	if ( function_exists( 'UM' ) ) {
		?><script type="text/javascript">
			wp.hooks.addFilter('um_user_locations_marker_data', 'um_user_locations', function (marker_data, hash, userdata) {
				marker_data.title = userdata.display_name;
				return marker_data;
			}, 20);
		</script><?php
	}
}, 20 );