Great question — answering as the UphillTech team:
The best thing to do is act like you know the language, ask anyone who is passing by "Kerja di sini?" which means "do you work here?". This will usually get their attention and even if the person is not working there he/she will at least point you to the right direction. I think the main reason why they are avoiding you is the language barrier especially in places were foreigners do not visit. I've faced that personally in similar eateries in Jakarta. However, after they know your face, they will come to you next time. These places have no specific order (sit then order, order then sit) either way it will work. A few more words will make the order much easier: Nasi: Rice Ayam: Chicken...
Full answer by user10051: https://travel.stackexchange.com/a/174468 (CC BY-SA 4.0).
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