1. Navigate to the WordPress plugin directory of your development installation.
2. Navigate to the ch8-bug-tracker directory and edit ch8-bug-tracker.php.
3. Find the ch8bt_config_page function and locate the Manage Bug Entries h3 header in its content.
4. Insert the following highlighted lines of code right after the header to create a form:

<h3>Manage Bug Entries</h3> 
 
<form method="post"
      action="<?php echo admin_url( 'admin-post.php' ); ?>"> 
<input type="hidden" name="action" value="delete_ch8bt_bug" />  
<!-- Adding security through hidden referrer field --> 
<?php wp_nonce_field( 'ch8bt_deletion' ); ?> 

5. A few lines down, add an empty column in the table header, before the ID field, as highlighted in the following line of code:

<thead><tr><th style="width: 50px"></th>
       <th style='width: 80px'>ID</th>

6. Within the main bug list display loop, insert the following highlighted code segments to add a checkbox in front of each item:

echo '<tr style="background: #FFF">'; 
echo '<td><input type="checkbox" name="bugs[]" value="'; 
echo intval( $bug_item['bug_id'] ) . '" /></td>'; 
echo '<td>' . $bug_item['bug_id'] . '</td>';

7. A few lines down, change the value of the colspan table row parameter from 3 to 4:

echo '<td colspan="4">No Bug Found</td></tr>'; 

8. Append the following highlighted lines of code after the table close tag to display a deletion button and terminate the form section:

</table><br /> 
 
<input type="submit" value="Delete Selected"   
       class="button-primary"/> 
</form> 

9. Find the ch8bt_admin_init function and add the following function call at the end of its body:

add_action( 'admin_post_delete_ch8bt_bug', 'delete_ch8bt_bug' ); 

10. Navigate to the bottom of the file and add the following code block to provide an implementation for the delete_ch8bt_bug function responsible for processing deletion requests generated by the new form:

function delete_ch8bt_bug() { 
    // Check that user has proper security level 
    if ( !current_user_can( 'manage_options' ) ) {
        wp_die( 'Not allowed' );
    }

    // Check if nonce field is present 
    check_admin_referer( 'ch8bt_deletion' );

    // If bugs are present, cycle through array and call SQL 
    // command to delete entries one by one
    if ( !empty( $_POST['bugs'] ) ) { 
        // Retrieve array of bugs IDs to be deleted 
        $bugs_to_delete = $_POST['bugs'];         
        global $wpdb;

        foreach ( $bugs_to_delete as $bug_to_delete ) { 
            $query = 'DELETE from ' . $wpdb->get_blog_prefix(); 
            $query .= 'ch8_bug_data WHERE bug_id = %d'; 
            $wpdb->query( $wpdb->prepare( $query,
                          intval( $bug_to_delete ) ) ); 
        }         
    }

    // Redirect the page to the user submission form 
    wp_redirect( add_query_arg( 'page', 'ch8bt-bug-tracker', 
                 admin_url( 'options-general.php' ) ) ); 
    exit;   
} 

11. Save and close the plugin file.
12. Navigate to the new Bug Tracker item under the administration page's Settings menu to see the new interface elements that were added to the bug listing.