How to make a 'Buy It Now' button below the ATC button that adds to card and takes to checkout?

[1KWF]

Hi wonderful people,,

I am using Debut theme. I want to know how to make a buy it now button that looks the same as the add to cart button and sits below it. That then adds to cart and sends straight to checkout. Basically how the Buy It Now button functions without the Dynamic Checkout option enabled. But when I disable that option the Buy It Now button dissappears. I want to keep that button there. If anyone can help me with this I'd really appreciate it, thank you!