Article in English: It's at the top of the menu. Again, you'll find this option at the top of the menu. It's in the middle of the menu. You'll find this near the bottom of the menu. You can also change your preferred difficulty here before selecting CUSTOM MATCH. You can change your game's difficulty, the campaign used, location settings, and any in-game settings from here. If you're joining a game that's being hosted by a friend, the campaign and in-game settings must be identical to the campaign and in-game settings that they're hosting. Doing so will bring up a list of matching servers. Once you find a game that you want to join, select it and then select JOIN. The game should begin soon thereafter.

Summary in Chinese:
选择开始游戏。 选择战役。 选择加入游戏。 选择自定义比赛。 选择游戏选项。 选择搜索。 选择游戏加入。