Both are played with white and black stones, but they play very differently. In go your object is to surround territory. If a group of stones is completely surrounded, then they are captured and taken off the board and counted toward your score. You can place a stone anywhere on the board so long as that stone has at least one liberty (a blank spot next to it or next to a line of adjacent stones of the same color) and so long as you don’t recreate a prior board position with the same player to play.
So really, the rules are simpler than Othello but the play is much more challenging. You get all sorts of abstract battle field type tactics, building supply chains, making converging forces, all sorts of stuff.