Hi,
The new PayPal Checkout API doesn't allow us to directly display the payment popup which appears when you click on the "PayPal" button of that screen. So what you want is not possible with PayPal Checkout.
The only way is to use the PayPal payment plugin, which uses the old API of PayPal. This will directly redirect to the payment page of PayPal after the user clicks on the "finish" button.
If you have a blank screen / popup when you click on the PayPal button, you must have this issue:
www.hikashop.com/support/documentation/4...out-form.html#issues
Supposing that the buttons are displayed, if you click on the "PayPal" button and you don't get the PayPal payment popup, or you get a blank popup on top of the normal popup, it's likely you have a problem with the Cross Origin Opener Policy of your website. You need to configure your HTTP headers plugin, via the Joomla plugins manager and change its "Cross-Origin-Opener-Policy" setting to allow for it.