first find our which IR sensor u will use.
simple photo diode or TSOP
based on this prepare proper interface circuit to connect it with micro controller
for stepper motor there are again two options
bipolar stepper motor or unipolar stepper motor
for bipolar stepper motor use L293/L298
for unipolar stepper motor use ULN2003/ULN2008
after finilasing circuit follow the tutorials for stepper motor control IR sensor interfacing on this site