How does this work? Coop?

[Derrame]

Hi

how does this game works? can I join a random group of players and play the main story? the sidemissions?
do I need a premade group?

can I join an already started mission?
can other random players join a mission that I started alone?

thanks

[Ixamesh]

There's automatic matchmaking (can't turn it off) for everything except for story quests and endgame activities. It can fill empty slots, but you have no control over it or the group members in that case. You can use official website[www.bungie.net], D2 companion mobile app (uses the same website) or community discord[discord.com] to find players. Check pinned Steam topics for more links.

You can invite or be invited to most ongoing missions. Everything can be done solo or with help of matchmade/LFG players, i.e. you don't need a clan or stack

[Nakos]

The campaigns can be played solo. Some of them have Legendary versions, those can also be solo, but if you're new, you might find them easier with a team. Do note though, having a team can make some aspects of play more difficult (having to do with respawns and revives (and whether or not you're in a restricted zone)).

Once you've completed a given campaign, there's frequently a rotating replay that includes automatic matchmaking.

The game has open world "patrol zones" these will have lots of other players in them and will have various Public Events that people will group up for, but there isn't any formality to it, it's just a bunch of Guardians working together.

There are also the playlists, those (at the Normal levels) all have automatic matchmaking. At the higher levels, you need a pre-made group.

And then there are dungeons and raids, and those are almost always premades (although some players can, and do solo dungeons).

[Pocahawtness]

You can also create random teams for things that don't have matchmaking by going to the Bungie website. They have a system that allows you to easily make or join teams doing a particular task. It's useful for Legend difficulty since matchmaking is usually off in the game.