I would say "Hyvä poika!"
hyvä
Good afternoon is hyvää iltapäivää in Finnish, however it isn't used very much. People usually say good day instead, which is hyvää päivää in Finnish.
'Ei hyvä'
'Hyvää lomaa!'
"Hyvää iltaa!"
Boy is 'poika'
"Olen hyvä." (Means I am good at something, or good in general.)If this was meant as a response to the question "How are you?" ("Miten menee" in Finnish), then the answer would be "Hyvin".
For you is sinulle in Finnish.
How is miten in Finnish.
Hyvä vastausAnd if you want to say something like:This is a good answer - you'd say:Tämä on hyvä vastaus
I am not Finnish. - (Minä) en ole suomalainen.
Goodnight is "hyvää yötä"