Concept of H-bridge
An H bridge is an electronic circuit that enables a voltage to be applied across a load in either direction. These circuits are often used in robotics and other applications to allow DC motors to run forwards and backwards. H bridges are available as integrated circuit, or can be built from discrete component.
H-bridge by using transistor
simulation of H-bridge concept
The LM293 internal circuit
The LM293 is an integrated circuit motor driver that can be used for simultaneous, bi-directional control of two small motors. Small means small. The LM293 is limited to 600 mA, but in reality can only handle much small currents unless you have done some serious heat sinking to keep the case temperature down. Unsure about whether the LM293 will work with your motor? Hook up the circuit and run your motor while keeping your finger on the chip. If it gets too hot to touch, you can't use it with your motor.