You can usually change to a story character in GTA5 Online through the game's menu options. Look for something like 'Character Switch' or a similar setting.
The new story might change the gameplay by adding new power - ups or abilities for the characters. This would change how players approach different situations in the game. Also, new areas in the map could mean new strategic points for combat or exploration.
First, launch the game. Then, navigate to the game's settings. Within the settings, there should be a language section. From there, you can choose the language you prefer. It's pretty straightforward.