Hey MK_Codes,
Sorry for the late reply, but I used Photon for the multiplayer. It's a package for Unity that you can get from the Asset Store. If you Google "Photon Unity" it should be the first few results.
The game is a few years old, but I think the version I used was PUN2. There may be a newer version by now but I'm not sure. It was available for free up to a certain amount of players and has good documentation and samples for learning.
Thank you!