From what I understand, 23 years is suppossed to be a hard limit, but I guess someone must have messed up a bit. Would think they get enough applications either way.
They do accept low time pilots, but as other people have said, only use email. Never just show up.
As for attire, any business casual thing will do. Don't need a full suit with a tie, but a collared shirt and some nicer style of pants would at least be a minimum. Some people show up with sandals and shorts, and are subtly hinted to maybe dress up a bit.
As for previous experience, there is no direct hire into the left seat of the caravan. You will at least have to spend 2-3 months in the right seat or so, if you have over a thousand hours. However, lately upgrades have become a lot more stringent, and you now have to pass several evaluations, interview etc.
For the Porter, afaik
there is no direct hiring into that one either, but I know of some FOs with lots of Porter experience, that had 1-2 months on the caravan, before being trained for the Porter.
The training bond is paid when you initiate your training. You do get paid during your training.
For the interview process, you will have to do the interview, go back home, wait a couple of weeks, and then get a start date. You will not stay in Indonesia (or well, you could, but I think it might be more expensive to stay for 2 months there).
I can answer any other questions you might have