Who finishes top of the league???

Hi,

Can anyone tell me what the rules are for determining who finishes first when two teams tie on points?

Is it then based on percentage/goal difference or does it come down to results between the tied teams?

I am VERY anxious to know the answer because my sons team may get duped out of 1st place and result in them playing the wrong team in the semi final tomorrow.

PLEASE help if you can