How to complete the network side of my game?

Hello community!

Start off, I understand the basics of network functionality. Got to have a dedicated server, and clients and so on.

I have created a simple mobile multiplayer type game where the level could spawn up to 4 players and do damage to each other and so on. So my main question is… creating a game through unreal engine 4 and making the multiplayer game work, Do I need to purchase a server or what? Like I’m totally confused on how this whole situation works for unreal.
I’ve read forums and forums and haven’t gotten a complete answer or tutorial on how to do so.
It’s only going to be for android at the moment going onto the google playstore since I already have a developer account with them.

So, who would be my server? Do I purchase a server? When game is created how do I have multiple rooms where people can join up to 4 players…

Thanks for all advice and answers!!