When you start the game, you will be shown a brief cinematic showcasing some of the games' characters, locations and Pokémon. Afterwards, you will be shown the title screen, which shows Kyurem in either its Black or White forme, depending on which game version you are playing. Press 
, and you will be taken to a menu where you can change various options and access certain features. Go ahead and select new game.
You will be greeted by Professor Juniper, the same Professor from Pokémon Black and White. She explains the basics of Pokémon and the Pokémon world, and asks for your gender and name. Your name has a maximum of seven characters, and cannot be changed later on, so choose it carefully. She will then ask for your rival's name, which also has a limit of seven characters. After a few parting words, the game will begin.