add items to cart using barcode scanner PHP

Im trying to create a single page containing a shopping cart . Items will be added when barcode is scanned i only need 5 products but always failed you can see what i tried... i know how to connect db but very little knowledge in php the items shall be added in an html table form but nothing is working

CREATE TABLE Products (
  ProductID INT PRIMARY KEY,
  ProductName VARCHAR(50),
  Barcode VARCHAR(50)
);
INSERT INTO Products (ProductID, ProductName, Barcode)
VALUES (1, 'Product A', '1234567890123'),
       (2, 'Product B', '2345678901234'),
       (3, 'Product C', '3456789012345'),
       (4, 'Product D', '4567890123456'),
       (5, 'Product E', '5678901234567');

php

<form method="post" action="scan.php">
  <label>Scan Barcode:</label>
  <input type="text" name="barcode">
  <input type="submit" value="Submit">
</form>

scan.php

<?php
// Connect to the database
$pdo = new PDO("mysql:host=localhost;dbname=your_database_name", "username", "password");

// Retrieve the barcode value from the form
$barcode = $_POST['barcode'];

// Prepare the SQL query to retrieve the product based on the barcode
$sql = "SELECT * FROM products WHERE barcode = :barcode";
$stmt = $pdo->prepare($sql);
$stmt->bindParam(':barcode', $barcode);
$stmt->execute();

// Check if there are any results
if ($stmt->rowCount() > 0) {
  // Start the HTML table
  echo "<table>";
  echo "<tr><th>Product Name</th><th>Product Description</th><th>Product Price</th></tr>";
  
  // Loop through the results and add each product as a row in the table
  while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
    echo "<tr>";
    echo "<td>" . $row['name'] . "</td>";
    echo "<td>" . $row['description'] . "</td>";
    echo "<td>$" . $row['price'] . "</td>";
    echo "</tr>";
  }
  
  // End the HTML table
  echo "</table>";
} else {
  // Display an error message if no results were found
  echo "No products found for barcode: " . $barcode;
}
?>

source https://stackoverflow.com/questions/76176199/add-items-to-cart-using-barcode-scanner-php