What are the procedures in NAIA terminal 1 to go to bangkok?

I promised my sister after her graduation that i will let her travel to bangkok and now, she has a 2 way ticket. what are the procedures in NAIA and other requirements she may bring to immigration counter? I need your feedback people especially she is a first timer to travel and because I tried it once how this officer cruel especially in tourist people. pardon me if I'm wrong. I experienced it when i was visiting my cousin.