Concrete5 - 无法从教程中添加新块basic_test

I'm following this official tutorial

http://www.concrete5.org/documentation/how-tos/developers/understanding-and-building-blocks-in-concrete5/

to add a new block to my fresh installation of concrete5. When I downloaded the zip and unzipped it in concrete/blocks, it says nothing is waiting to be installed under Block Types. When I place it in application/blocks, it gives an error "Class 'BlockController' not found". I already tried clearing the cache. I am using concrete 5.7.2

What am I doing wrong? Thanks

I did the below and it seems to be working. Not really certain about the Namespace

<?php
namespace Application\Block\BasicTest;

use Concrete\Core\Block\BlockController;

class Controller extends BlockController {
    
    protected $btTable = "btBasicTest";
    protected $btInterfaceWidth = "350";
    protected $btInterfaceHeight = "300";

    public function getBlockTypeName() {
        return t('Basic Test JR');
    }

    public function getBlockTypeDescription() {
        return t('A simple testing block for developers');
    }
}
?>

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