Open Question: HOW VIETNAMESE BUY HOUSE IN USA? WHO CAN I CONTACT?

hello,may name is SON TRAN,my MOM and DAD are want to buy a house in LA,CA,USA .we also find a good one.and how can we buy it?who can I contact to? how about tax fee in there? do I need to fix that house while I got to bought? and how much to fix that house? when my parent got to buy that real estate? so could our family can live in USA and be a citizen of USA? thanks you for your reading my message.any ny contact just contact to my email ( jimmy_tran1@yahoo.com ) or my phone number ( +84907815397 ) I want to asked for my parent. thanks you for your care. SON TRAN