PayPal problem

[Littlepants]

I have recently had problems with PayPal payments. They are not functioning properly. I have looked at the configuration,and don't' understand it. I have set it the following way

 

Express Checkout shortcut

Offer your customers a 3-click checkout experience

 Yes
 No

Use the PayPal Login functionnality(*see the integration guide and follow the steps)

This function allows to your clients to connect with their PayPal credentials to shorten the check out

 

 Yes

 

Now I certainly don't want the express checkout short cut. But the second option I am having trouble understanding. If I change it to 'yes' and look at the integration guide, I can't make head nor tail of it. What is my 'Client ID'? And what does 'Secret' mean? And what are these templates?  

 

The integration guide is total gobbledygook to me. I haven't a clue what it's on about. 

 

For the meantime, I have gone through the configure process again, to see if this corrects the issues I'm having, and have left it as not using the PayPal Login functionnality. But could it be this that is causing the issues?  Attached is a photo of what is happening when customers try to pay with PayPal