The chess board and its 8 ranks, 8 files, 32 pieces and 64 squares gives an enormous amount of possible moves and chess openings. According to the online chess server Lichess, there is more than a thousand named and known chess openings, that is registered by their unique portable game notation (PGN) in the database.
The purpose of a chess opening is to develop strong positions and attacks. This is done by first moving one or more pawns out. Then it is time for knights and bishops to enter the game, because these pieces can attack from behind the pawns and prepares for castling at the same time. If you want to castle, it should be done early at this point. These opening moves concludes a chess opening. The middle game begins.
The reason, that it is worth studying chess openings is, that many of these moves should be automatic, so you save valuable time, because the moves will be the best known responses to certain moves from your opponent. It might be a good idea to learn a few basic chess openings first and then exploring more advanced chess opening later.
If you would like to begin with a simple, basic and aggressive chess opening, then I recommend my little introduction to the Ruy Lopez chess opening.