Well, you haven't left very much information. Is he in school yet? How old is he? What are your concerns?
Many things can look like add/adhd and there is a lot of variability in younger children with regards to behavior, impulsivity, focas and energy so it can be hard to tell. In our area, kids aren't even evaluated until the earliest of 6 years of age for that reason.
But with no further information from you, a simple answer is that you see a child psychiatrist that specializes in add/adhd for an assessment. good luck
Yes, give us some more info.