One-Page Checkout [Support Thread]

[jiji2018]

No I cannot because I don't know where in your template you have checkout buttons.

Checkout button on the shopping cart page
As shown in the screenshot below

[mprough]

Checkout button on the shopping cart page
As shown in the screenshot below

That edit, depending on your template is in includes/templates/your-template/templates/tpl_shopping_cart_default.php

[jiji2018]

That edit, depending on your template is in includes/templates/your-template/templates/tpl_shopping_cart_default.php

This link should be judged by existence, where is the real link modified?