There is no coordinated multiplayer.
You will see other players eventually, but certainly not at the start of the game. It may take weeks of playtime to run into another player.
When you do, there won't be any indication they are another player. If they do weird stuff, you can tell, but there is no direct communication or chat. There is no co-op/team stuff in the game. There is no player-to-player trading either. I'm not sure if you can even attack another player inside or outside their ship, in PvP fashion.
All you can really do together is follow each other around. If you choose to, you can both attack the same targets and what not, but it's more of a base-level cooperation. Any materials that drop from destroyed ships or rocks or whatever are on a first-come/first-grab basis with no assigned loot, so far as we know.
Other players are pretty much just added ambient immersion in the environment.
Sean DID say, however, they might add a more traditional multiplayer system down the road, but at the start, it's just you, your ship and a bunch of planets to scan.
If you desperately want to play with someone, you will basically have to get a player's Gamertag ID, add them to your friends list at the console level, and communicate with them via 3rd party chat/VOIP. Like PSN, XBL or Steam. But even then, you're going to have a hell of a time trying to find the person you're looking for unless the game uses a common constellation arrangement where players can actually star-map themselves to a rendezvous point of some sort.
