The chess board consists of 64 squares arranged in 8 by 8 squares, 32 squares are white and 32 black. Chess squares are named, sometimes referred to as notations, from left to right from a to h and numbered from bottom to top 1 to 8. So if you were asked to name the bottom leftmost square, its 'a' because its the left most square and then number '1' because its bottommost from the top. This square will be 'a1' and the one to the right will be 'b1', the one next on top is 'a2'.
So how to you write each square for all the chess pieces? In chess notation, pawn is identified by its square letter and number, so pawn at b2 will be represented as 'b2' but lets say there is a bishop at c4, then it will be written as Bc4, and for a rook on c4, it will be Rc4 or a queen as Qc4 so on so forth. Example below shows bishops on different squares and their chess notation.