i need to know

You host and wait for people to join.

On the PSP version you can select host or join. When you choose join, it searches for a short time and then gives up if it doesn't find anything. On the PSP version, you can wait until the number of players you want joins before you start.

On the DS, everyone chooses a game type (race, deathmatch, fort) and then the number of players wanted. It searches until it finds the opponents who selected the same options or until you cancel the search. It seems to be better for finding a 2 player game than the PSP system but the PSP system is better for finding a 3 or 4 player game.

I think both versions allow all players to vote for the scheme and landscape after they have connected.