Hi,
Well, it depends what you want to do.
- You could disable the "HikaShop cart notify" plugin via the Joomla plugins manager so that you wouldn't get the add to cart notification and in that case, you would be redirected automatically to the checkout.
- You could instead change the settings of that plugin to display a centered popup with a "proceed to checkout" button.
- You could also enable and configure the HikaShop cart module via the Joomla modules manager to display a cart module in a position of your template. Such module also has a setting to display a "proceed to checkout" button.
- You could also create a menu item of the type "HikaShop checkout" so that the customer could click on that menu item to access the checkout.
You can potentially implement one or several of these points. It's up to you how you want to handle the access to the checkout.