Web-shop and Information-site combined.

[Shopify]

Hi.

I saw this fine looking site that combines a wordpress site with a PS in a menu. 

https://artipoppe.com/

How do you think this is done as I would like to know how to do that as we had a big information-site as a fundamental knowhow for products of our shop and would like to do something similar.

1. Is both sites on the same server?
2. Both DB's in the same SQL?
3. Where or which should be the root install ex. wordpress root and shop in /shop/ ??
4. Is it a plugin/module to combine the menu's to one.
5. Anyone know of a guide to study about combining this?

Any answer is much appreciated!

Thank you for your valuable time.