Integrating PayPal into a website -- 2

Hello,

I need help following PayPal integration Instructions on https://developer.paypal.com/docs/checkout/standard/integrate/
If you have experience with this I will need you to "explain it" to me and walk me through it step by step.

First you will need to show that you understand the instructions by running the demo on your computer and showing your work.

I cannot expect you to show me how to run it if you have not run it yourself.

Thanks