Nothing to worry, for an exclusively breast fed baby it is normal to pass stools once a week or pass 5-6times per day. Yellow or green color is fine.
Next Steps
In case the baby is passing hard pellet like stools or there is blood or mucous(white phlegm like) in stools then consult a pediatrician
Health Tips
You could put the baby on his/her tummy for sometime, say about 15mins in the morning and evening it will ease the bowel movement.