Making a fps online game

Hi guys im trying to make an online multiplayer fps.How can I make the game multiplayer.

Read through Leepo's networking tutorial here:

http://forum.unity3d.com/viewtopic.php?t=30788

leepos’s tutorial dosen’t work any more

You might consider running a search for Photon in the asset store. Their cloud-hosted networking works well, and is free for a small game, and affordable for a larger one.