Archive template

I have several custom post types and we need to create separate archive templates for these. I tried the following advice, but it’s still using the default archive template.

In the form of the single-type-template. In the same way that posts
are shown on their own page with single.php, custom post types will
use single-{posttype}.php if it’s available.

So for the above example, you could create a single-acme_product.php
file and the product posts would be shown using that template.

In the form of the archive-type-template. In the same way that posts
are shown on their own archive with archive.php, custom post types
will use archive-{posttype}.php if it’s available.

So for the above example, you could create a archive-acme_product.php
file and the product posts would be shown using that template.

Any help would be greatly appreciated.

Here is my code

function camps_register_post_type() {
   register_post_type('camps', array(
       'labels' => array(
           'name' => 'Camps & holidays',
           'singular_name' => 'Camps & holidays',
           'add_new' => 'Add New Camps & holidays',
           'edit_item' => 'Edit Camps & holidays',
           'new_item' => 'New Camps & holidays',
           'view_item' => 'View Camps & holidays',
           'search_items' => 'Search Camps & holidays',
           'not_found' => 'No Camps & holidays found',
           'not_found_in_trash' => 'No Camps & holidays found in Trash'
       ),
       'public' => true,
       'has_archive' => true,
       'rewrite' => array("slug" => "camps"), // the slug for permalinks
        'supports' => array('title', 'editor', 'thumbnail')
   ));
}

For custom post type with slug camps:

• Single post template: single-camps.php
• Archive index template: archive-camps.php