It is a weird phrase. Translated literally from English it's "what's news?" but when learning Bahasa as an English speaker it is "how are you?". It is a versatile phrase and I think it is something that will be ironed out considering this is the first time the beta has gone truly public.
"How do you do?" does not mean "Apa kabar?", instead it means "Hi!" or "Hello!"
When someone says it to you, you also have to answer "How do you do?"
The same case also often happens in Chinese. There are two expressions: • 你好! (ni hao) = Hi!; Hello!; How do you do? • 你好吗? (ni hao ma) = How are you (doing)?
你好! (ni hao) is often translated as "Apa kabar?"; "How are you?" It is wrong! When someone says "你好!" to you, you have to answer "你好!" as well.
Oh, my. I have spoken and studied and sometimes taught English for almost 80 years now and I have never heard "How do you do?" answered by "How do you do?" even in the movies. I have always understood the proper reply to "How do you do?" to be "I am fine (or "Very well") thank you. And you?"
The only difference in meaning between "How are you?" and "How do you do?" is level of formality. Today, "How do you do?" sounds extremely formal and even stodgy, so only old folk like me remember it being used regularly. One would always use it in a formal introduction, for example.