Sage Api intergration in Magento 2

Hi All,

I am a newbie to the sage world. I want to consume sage API's to sync orders and customers in my Magento demo application. I am a bit confused about which sage application api to work with. Can anyone suggest? 
And at the time of registering in the sage developer, it is showing limited countries, So  How I can register myself in the sage developer and use its API as I am from an Asian country. This might a basic question to all but really need your help in understanding Sage.