Help to make a general multiplayer game

Ok, so I’ve checked out more into Epic Online Services, I got the SDK and did research but I seen something about the EOSCore exposed in the blueprint plugin… EOSCore in Code Plugins - UE Marketplace is this needed? Also, I’m not sure how to use the Epic Online Services SDK. So what exactly do I need to use and get to be able to create a multiplayer game for free in ue4?