Code Challenge HTML Forms

I'm stuck on task 3 in PHP (HTML Forms). It asks to: "Finally, we need the form to submit a unique identifier for the order to the process.php file. We need to be able to access that value in an “order_id” element of the $_POST array like this: $_POST["order_id"]. For this particular order, the order ID should be 7546. We don’t want this value displayed in the browser. What do we need to add to the form? (Hint: We need to add a new HTML element with three attributes.)"

Here's my code:

<p>Your order has been created. What flavor of ice cream would you like to add to it?</p>

<form action=process.php method=post> <input type="hidden" value="Flavors"> <input type="hidden" value="order_id" name="7546">

<input type="hidden" value="7546" name='order_id'>

<label for="flavor">Flavor</label>
<select name="flavor" id="flavor">
    <option value="">&#8212; Select &#8212;</option>
    <option value="Vanilla">Vanilla</option>
    <option value="Chocolate">Chocolate</option>
    <option value="Strawberry">Strawberry</option>
    <option value="Cookie Dough">Cookie Dough</option>

</select>

<input type="submit" value="Update Order">

</form>