PRoduct options drop down isn’t showing in my theme

I am trying to add a product to my store that is available in different colours.

I’m hoping that the customer would choose the colour from a drop down, select the quantity, and then add it to their cart.

I have added it correctly in the back-end, and even linked the colours up to their respective SKU’s. The drop down for the colours simply isn’t showing up on the front-end.

I installed and tested it on the storefront theme, and it shows up and works just fine through that – so I’m led to believe that my theme is at fault.

What code would I need to conditionally show up a drop down if a product has variations?

This is a snippet of my current content-single-product.php page, where I assume this code would live:

    <form method="post" enctype="multipart/form-data">
    <div class="input-group spinner">
    
    <input type="text" class="form-control" step="1" min="1" max="253" name="quantity" value="1" title="Qty">
    
    <div class="input-group-btn-vertical">
    <button class="btn btn-default" type="button"><i class="fa fa-caret-up"></i></button>
    <button class="btn btn-default" type="button"><i class="fa fa-caret-down"></i></button>
    </div>
    
    </div>
    
    <input type="hidden" name="add-to-cart" value="<?php echo esc_attr( $product->id ); ?>">
    <button type="submit" class="single_add_to_cart_button btn btn-cart">Add to cart</button>

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