Hi man,
There are a lot of tutorial about multiplayer and i am a little lost too sometimes,
here people more expert than me could write down a lot of stuff…
But the the way you didnt point any problem speccificly so i assume:
Probably on multiplayer you get problem with, replication and authority.
Who should manage the hud and who should create it, and from wich variable?
The first things is your multiplayer is client-server or on the same machine?
Here you can find all the basics Networking and Multiplayer | Unreal Engine Documentation
here something to start 1.2 - Detecting Network Authority and Remote Clients in Blueprints | Unreal Engine Documentation