I have made an online game that works! 
Everything works except for the terrain generation. Now the terrain generation is fine for singleplayer because no one else is going to join you. But when i play multiplayer the terrain generates a new world for every user. When you look around you can see people underground and it will seem as if they are falling but on their screen there is terrain because the terrain that their game generated is not the same as another player’s terrain. This is a minecraft clone. Here are screen shots. Also i cannot acess the inventory for some reason but ill do that on my own.
Make sure everyone uses the same random number seed, and executes all of randomization in exactly the same order. Generate the seed on the server, and send it to each client.