Studying in Indonesia

Thats an interesting topic and its depends on which subject this particular student is studying and what that student is looking for during such a semester abroad.
1. If the student is studying in the field or art, dance, painting, sculpturing and culture as a whole it is deeply suggested to get in contact with the Indonesian culture. But one month wouldn't be enough to learn about this amazing culture, because it is so unique and divers. Indonesia has over 17.000 Island the big island like Java, Sumatra and Kalimantan are divided in 7 districts with each containing 7 or 8 ethnical groups with different languages, traditions and culture. So you can imagine how diverse this culture is. But I also have to say that this is just for basics as well, if this particular student is searching for higher knowledge for scientific research reasons, the educational system is not offering that, as well the standard and methodology of teaching and learning is on a very low level.
2. If the student is studying psychology or any study in a social field it is also suggested to get in contact with old healing traditions of the different parts of Indonesia, special in Bali, additional to learn a different perspective of social life. Also in here I need to say, that you will always just be able to absorb basic knowledge, to get deeper inside the traditional healing sector you would need years and a very strong character to develop private connection to the traditional healing system. This is also not meaningful in case of scientific research students. But anyway very interesting to get a different view of social behaviors and problem solving solutions in basics as an addition to western or any other social approaches.
3. for all other studies I would say it is not suggested, because the general quality of studies is below average bad. Docents are not qualified enough to deliver subjects in the right way, with the right knowledge as well. And if they have the right knowledge they are not qualified enough to deliver the knowledge as a qualified teacher. This is wasting time, accept this particular student is looking during his study also for side knowledge which he/ she will have to collect him/herself during the stay in Indonesia. Indonesian people have in many things of the daily life a very different approach to deal with problem solution. But if this particular student is just searching for knowledge I would say it will be wasted time.
In general I would say that government Universities are more trustworthy than private universities. Private Universities promising a lot, but in the end you pay a lot but you never get what they promise, the standard of teaching is also much lower than in government universities, at least they are under a kind of supervision of the government. But don't expect a good quality of teaching in any of the universities, that for the education in the field of teaching methodology is below average bad and even worse the awareness of having knowledge of teaching methodology is very low.

Damasiswa Program, a 6 month and 1 year scholarship for young foreigners from the Ministry of Education and Culture. You can get all info on http://darmasiswa.kemdikbud.go.id/

I'm a student from Vietnam and I'm very interested in Indonesia education system

You mean you're now studying in Indonesia or you're still in Vietnam?