Hi @ssaha,
in addition to what @MargaretC has shared in her papers and will share in this year's Forum, which gives the best overview you can get at the moment in this regard, my best recommendations for you are very simple and also of main importance:
Before anything else, please get an IT service provider who has good IT knowledge on AWS, who can set proper Network, Security and assess performance as indicated on Margaret's paper. If you can get it, and you have your VPN, your domain controller, your network, you will be fine. If not, your business is sold to risks and most probably frustration.
Also, once you have a good AWS service provider, I suggest you to have a SAS Consultant or especialized SAS partner to do assess and draw the architecture of the system and processes that are adeqcuate for your business and the migration, and to open the communications between SAS and your AWS IT provider, to ensure everyone is in the same page.