The school will take care of your work permit so if you have the proper documentation it will not be a problem. All countries want to protect their own citizens so they do not take kindly to "foreigners" taking jobs in their countries, especially high paying jobs like teachers at international schools . You will be paid far above the average workers wage for teaching. Therefore the paperwork will be onerous but if you have all of the required paperwork some human relations person will do it and not you.
Having said that, you better bring all of the paperwork they ask for which will probably be a police check, original copies of your degrees, transcripts from your university and so on. I hate to give original copies of degrees because they sometimes get lost and you will have a lot of work to get your university to issue another copy.
Here is my advice. As soon as you get your work permit, ask for your degree back. If you are lucky, they might accept a lawyer's affidavit that the "copy" of the degree you give them is true and original. That way you can keep your degree locked up at home where it belongs but check this out before you leave your home country. If they are sticky you will not be able to work overseas.
Here is why. Asian countries are close together and you will want to go away on long week-ends to another country. To get a visa before you leave in your home country is expensive and cumbersome. Do you want to have to do it again from a foreign country?
I thought not. Therefore you want to get a multiple entry visa so you can go and come as often as you wish. No problem, right, you just pay a little more money and you buy a multiple entry visa.
Wrong. You cannot get a multiple entry visa UNTIL you have a work permit and getting a work permit takes time because of all the bureaucracy the school has to go through, assuming the school is efficient. If you start in September, and you get a holiday in October, do not be confident you will be leaving the country that holiday!!!
Just a word to the wise about planning holidays. It could take a month or two to get a work permit... and you need a work permit before you can get a multiple entry visa!