Take a look at various network options. Here’s a link below with some options. See which ones fit with your requirements and try one or more of them out. As already mentioned there is no such thing as “easy” networking. Even a relatively simple networking project is a big project, expect a networked multiplayer version of your game to take 3X as long to develop as a similar single player version of the same game.
I haven’t used Photon Bolt, but all the Photon products are generally well received.