I would really like to make a multiplayer game on unity but I don’t know how or if it is even possible.
Have you made any games on Unity before? A multiplayer game is hard work on top of building a game. If you’re completely new to Unity you should take a look at the Lerpz Tutorial here 3D Game Kit Reference Guide - Unity Learn
If you’ve built a game before in Unity, you should build the game as normal and then ask specific questions about integrating multiple players.