Learn the notation, watch the classic openings, practice them, then play them against the computer.
Play the book moves yourself. The site answers with the other side. Click a piece, then a square.
The computer plays the opening's book moves, then Stockfish takes over. You can play anything.
Every square has a name: a letter for the column (a–h) and a number for the row (1–8). Moves are written as piece letter + square, like Nf3 = knight to f3.