Does anyone have a sample of certificate of employment letter for DTV ? What does it have to contain?

I have asked this question before but it was some time ago when my partner was pregnant, I am an Australian and i now have thai twins to my partner, they were born on the 13 September, so yes there only a couple of months old, I was there for there birth and I am on there birth certificate and they have my last name, the question is about Australian citizenship by Decent, will it be easier to do through the embassy in Bangkok or do in Australia, and what does the process involve. If you have done something like this, any advise would be greatly appreciated.