In small criminal case.
The first instance, Accused was sentenced guilty and 5000 Bahts fine, without lawyer.
If the Accused want to appeal within 30 days, Appeal form or document can be sent to the Courts of first instance by postal registered mail ? or Appeal form must be carried in to the Courts by the accused hand ( if without lawyer) ?
The Accused has no Lawyer.
Your questions shows that you are lacking the basic skills to defend yourself. Especially in a criminal matter, especially if you are a foreigner (for communication reasons and the fact that you might have high consequences to your convictions) you should consult a Thai lawyer. (Not online)
If you do not have the money to pay a lawyer, simply go at the same court where you were convicted. You should see the clerks there and ask them.