How can I modify checkout.liquid for better coupon visibility on mobile?

Dear Community,

I would like to ask for your help on a coding matter on Shopify. Our shop has a custom built checkout, but unfortunately the developers who built it are no longer within the reach of the company.

On mobile above the quick checkout options the customer’s cart is in a drop down menu, that by default is closed, the option to add a coupons is also in this drop down menu, so some of the customers are having issues finding where to add the coupons.

I know that I would have to alter the checkout.liquid file in the themes coding, but I don’t exactly know what code I should be using. Could you maybe help me with this question?

I’m attaching a screenshot of the issue, I think that helps understanding what I would like to change.

Thank you in advance!

Kind regards,

Greta