PHP - Documenting Thrown Exceptions.

I'd love to use anonymous placeholders on my ecommerce site project.  I am writing half with php and half with golang.  On the three examples below, when run, gives the following exception, " Error: Call to a member function execute() on string. "  I tried it with a decimal too.  Thanks in advance.
 

$stmt = $dbo->prepare = ("SELECT * FROM products WHERE ProductName = ?");
//this one calls exception
$stmt->execute();

$stmt = $dbo->prepare = ("SELECT * FROM products WHERE ProductName = ?");
//this one calls exception
$stmt->bindParam(1, $productID, PDO::PARAM_INT);
$stmt->execute();

$stmt = $dbo->prepare = ("SELECT * FROM products WHERE ProductName = ?");
//this one calls exception
$stmt->bindValue(1, $productID, PDO::PARAM_INT);
$stmt->execute();

Here is the rest of the code :

<?php
$filename = "";
$keyword1 = $_GET['keyword'];
$titleOfSelectedDropDown = $_GET['val1'];
$fileID = "";
$imageID = "a";
$displayID = "";
$keyword1 = "test";
$titleOfSelectedDropDown = "cc";

$host = 'localhost';
$user = 'root';
$pass = '';
$database = 'ecommerce';

$options = array(
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_EMULATE_PREPARES => false
);

$gKeyword1 = "";
$gKeyword2 = "";
$gKeyword3 = "";

$key1ID = "";
$key2ID = "";
$key3ID = "";

$string1 = "<center><h1><u>Search Results</u><h1></center></p>";

$dbo = new PDO("mysql:host=$host;dbname=$database", $user, $pass, $options);

$stmt = $dbo->prepare = ("SELECT * FROM products WHERE ProductName = ?");
$test = "1";
$stmt->execute([ $test ]);

Hi guys. I have a record shop online.

The following URL example shows the product info page without a problem:

http://www.mysite.com/tp/html/product/33/record1.html

Im using an .htaccess file as follows:

RewriteEngine On
RewriteRule ^product/([0-9]+)/(.*).html$ detail.php?id=$1 [L]

My problem is that the sound files are in a different folder on the server :

www.mysite.com/sf/soundfile.mp3

The mp3 sound files are not found or shown on the detail.page as they are in a different folder which doesnt have a rule associated with it. It doesnt need one as the mp3 file doesnt need SEO referencing.

How do i tell the .htaccess file to look in the sf  folder to find the mp3 files on my detail.php page?

thanks!