work with paypal without requiring login

I'm trying to build a very small and simple online shop, my customers don't like the idea that they have to register an account and login before they can place orders, so I am planning to build the shop using paypal buttons, which will lead customers to paypal page to checkout. I can manually add paypal buttons for every item I'm selling, but as my business grows, there are more and more products to add, so it won't be a wise idea to do that. Furthermore I want the products to be more organized and the layout more attractive, so my question is:
can hikashop work with paypal without requiring users to login? Or more specifically, can hikashop generate paypal checkout buttons with product informations having been input?

I have created a payment method using PaypalExpress Plugin, but on the checkout page, there is an error message saying no payment method found.
Then I try creating a payment method using PaypalStandard Plugin, this time ,only this payment method shows. I guess there is something wrong with my setting for PyapalExpress. What could it be?

P.S.: I've made sure the plugin is published. So I guess the problem is with the "Specific Configuration" section. Not knowing what to fill, I leave it as it is. I also click "help" to see instructions, but there is an HTML error on this page and it is not helpful. So how do I fill out those API blanks?

And why do I not need to fill these "API" blanks with PaypalStandard?

Thank You! I have got the correct API credential including username, password and signature, I also changed the API version to the current version 116. But when I click button "check out with paypal" I have got this error message:
Connection failure - error code : 10525 , error message : This transaction cannot be processed. The amount to be charged is zero.

Please help.