I need to learn the particular Arabic which can be understood in Palestine

Both are correct but its Tamam not Tamen , its common Arabic expression anyway i can teach you Arabic (Egyptian) its can be understood in any Arab country.

I need to learn the particular Arabic which can be understood in Palestine

Salaam aliekum. Kief Halek?
Alhumdulilla

Tamen: the correct expression is "you are doing a good job" or "you are doing well."

As-salam alaykum . Kief Halek?
Alhumdulilla 

tamam (you doing good)