How do mainlanders go to work in Hong Kong? My sister immigrated to Hong Kong and got married there. What is the procedure?

You have to immigrate to the past, otherwise you are not a new immigrant, not a Hong Kong resident, and it is hard to find.

Otherwise, it will be very difficult for mainland citizens to work in Hong Kong, because employers will hire you.

But if you want to hire you, that employer can only import foreign workers if he can't find qualified workers in Hong Kong.

After all these are confirmed, you can ask your employer to apply for a work permit for you, and then you can go to work in Hong Kong.