New RPG Looking for Assistance (Of any kind)

I’m new to networking and still learning everything else (modeling, animating, programming) but I can’t really go forward with my project until I setup a network with UE4. I have a basic understanding of what I need and could really use some more insight on the connection between UE4 and my web server. I know it’ll most likely be using php so I kind of need some help with the programming of my network. I downloaded the JSON Query plugin for UE 4.8 and have a basic understanding of what to do (Blueprint wise) to connect to my web server. But Server side, what do I need to do to connect UE4 to my database. (I know that ue4 doesn’t actually connect directly to the database, rather the web server just shares information from the database) But how does the web server know what requests ue4 has and how does it tell ue4 the correct information? I’ve searched the web for a bit and havent really found anything suitable but maybe I wasnt searching the right keywords. Any help? Thanks.