Add custom field and custom posts wordpress

<?php
	function create_post_your_post() {
	register_post_type( 'your_post',
	array(
	'labels' => array(
	'name' => __( 'Your Post' ),
	),
	'public' => true,
	'hierarchical' => true,
	'has_archive' => true,
	'supports' => array(
	'title',
	'editor',
	'excerpt',
	'thumbnail',
	),
	'taxonomies' => array(
	'post_tag',
	'category',
	)
	)
	);
	register_taxonomy_for_object_type( 'category', 'your_post' );
	register_taxonomy_for_object_type( 'post_tag', 'your_post' );
	}
	add_action( 'init', 'create_post_your_post' );
	function add_your_fields_meta_box() {
	add_meta_box(
	'your_fields_meta_box', // $id
	'Your Fields', // $title
	'show_your_fields_meta_box', // $callback
	'your_post', // $screen
	'normal', // $context
	'high' // $priority
	);
	}
	add_action( 'add_meta_boxes', 'add_your_fields_meta_box' );
	function show_your_fields_meta_box() {
	global $post;
	$meta = get_post_meta( $post->ID, 'your_fields', true ); ?>
	<input type="hidden" name="your_meta_box_nonce" value="<?php echo wp_create_nonce( basename(__FILE__) ); ?>">
	<p>
	<label for="your_fields[text]">Input Text</label>
	<br>
	<input type="text" name="your_fields[text]" id="your_fields[text]" class="regular-text" value="<?php if (is_array($meta) && isset($meta['text'])) { echo $meta['text']; } ?>">
	</p>
	<p>
	<label for="your_fields[textarea]">Textarea</label>
	<br>
	<textarea name="your_fields[textarea]" id="your_fields[textarea]" rows="5" cols="30" style="width:500px;"><?php echo $meta['textarea']; ?></textarea>
	</p>
	<p>
	<label for="your_fields[checkbox]">Checkbox
	<input type="checkbox" name="your_fields[checkbox]" value="checkbox" <?php if ( $meta['checkbox'] === 'checkbox' ) echo 'checked'; ?>>
	</label>
	</p>
	<p>
	<label for="your_fields[select]">Select Menu</label>
	<br>
	<select name="your_fields[select]" id="your_fields[select]">
	<option value="option-one" <?php selected( $meta['select'], 'option-one' ); ?>>Option One</option>
	<option value="option-two" <?php selected( $meta['select'], 'option-two' ); ?>>Option Two</option>
	</select>
	</p>
	<p>
	<label for="your_fields[image]">Image Upload</label><br>
	<input type="text" name="your_fields[image]" id="your_fields[image]" class="meta-image regular-text" value="<?php echo $meta['image']; ?>">
	<input type="button" class="button image-upload" value="Browse">
	</p>
	<div class="image-preview"><img src="<?php echo $meta['image']; ?>" style="max-width: 250px;"></div>
	<script>
	jQuery(document).ready(function ($) {
	// Instantiates the variable that holds the media library frame.
	var meta_image_frame;
	// Runs when the image button is clicked.
	$('.image-upload').click(function (e) {
	// Get preview pane
	var meta_image_preview = $(this).parent().parent().children('.image-preview');
	// Prevents the default action from occuring.
	e.preventDefault();
	var meta_image = $(this).parent().children('.meta-image');
	// If the frame already exists, re-open it.
	if (meta_image_frame) {
	meta_image_frame.open();
	return;
	}
	// Sets up the media library frame
	meta_image_frame = wp.media.frames.meta_image_frame = wp.media({
	title: meta_image.title,
	button: {
	text: meta_image.button
	}
	});
	// Runs when an image is selected.
	meta_image_frame.on('select', function () {
	// Grabs the attachment selection and creates a JSON representation of the model.
	var media_attachment = meta_image_frame.state().get('selection').first().toJSON();
	// Sends the attachment URL to our custom image input field.
	meta_image.val(media_attachment.url);
	meta_image_preview.children('img').attr('src', media_attachment.url);
	});
	// Opens the media library frame.
	meta_image_frame.open();
	});
	});
	</script>
	<?php }
	function save_your_fields_meta( $post_id ) {
	// verify nonce
	if ( isset($_POST['your_meta_box_nonce'])
	&& !wp_verify_nonce( $_POST['your_meta_box_nonce'], basename(__FILE__) ) ) {
	return $post_id;
	}
	// check autosave
	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
	return $post_id;
	}
	// check permissions
	if (isset($_POST['post_type'])) { //Fix 2
	if ( 'page' === $_POST['post_type'] ) {
	if ( !current_user_can( 'edit_page', $post_id ) ) {
	return $post_id;
	} elseif ( !current_user_can( 'edit_post', $post_id ) ) {
	return $post_id;
	}
	}
	}
	$old = get_post_meta( $post_id, 'your_fields', true );
	if (isset($_POST['your_fields'])) { //Fix 3
	$new = $_POST['your_fields'];
	if ( $new && $new !== $old ) {
	update_post_meta( $post_id, 'your_fields', $new );
	} elseif ( '' === $new && $old ) {
	delete_post_meta( $post_id, 'your_fields', $old );
	}
	}
	}
	add_action( 'save_post', 'save_your_fields_meta' );

https://www.taniarascia.com/wordpress-part-three-custom-fields-and-metaboxes/