As a teacher, you have to expect that quite often you are going to get drawn into arguments between pupils. This often starts right from reception and is usually arguments over toys or friendship groups. Often this is not bullying, more just young children learning about how to behave and how to treat others in the right way, but it is always important to keep an eye on persistent problems that come up again and again. If for example, you have two children who are always falling out, try and work out if it is one-sided or if they are both causing the issue. If it is just one child then it is important to check that this is not a case of bullying. Often with younger children distraction can work well and it may even be the case that you put two children that usually do not get along together to work on something.
If you have not seen what has occurred during a fall out then it is often not to try and guest and instead explain that you do not know what has happened but reiterate what kind of behaviour you expect from both of them. Explain how important honesty is and try and encourage the children to tell the truth.