Making a full wave rectifier can be difficult but it's simpler if you build it in two stages. Here LEDs are used to bring the circuit to life. First a line of 3 LEDs are connected in the same direction so they all come on when the current is in the right way. Two more LEDs are then added in the other direction and connected to the central LED so that all 3 are in the same direction. These LEDs light when the current is in the other direction. Maybe it's better to explain with an animation.