How to open a web browser for a Run/Debug Configuration in PhpStorm?

My specs:

• OS: Arch Linux
• WM: KDE Plasma
• PHP: 7.2.1 (with XDebug)
• PhpStorm: 2017.3.3

I have these settings in PhpStorm:

When starting PhpStorm, the port 7999 is always listening. I have to start manually the web server specified in "Run/Debug Configuration" then port 8000 is listening too.

My problem is when trying to run any script from editor by using browser popup, i.e., this file:

~/Projects/PHP/LearningPHP/ch01/ex0102-form.html

By using browser popup, web browser opens this URL:

http://localhost:7999/LearningPHP/ex0102-form.html?_ijt=cfvfi8l80ks1r42h10and6krpr

and I can get one error if this file is calling another file located in subdirectory "ch01".

I'd wish this browser popup opens the resource according to "Run/Debug Configuration", meanwhile I have to input manually in web browser this URL:

http://localhost:8000/ch01/ex0102-form.html

So I have three questions:

1. How can PhpStorm be configured according to my wish?
2. When and What is port 7999 used for?
3. What's the difference between services using ports 7999 and 8000?

Thanks in advance.