NVC will schedule interview for you once all copies of documents

1. NVC will schedule interview for them once all copies of documents have been submitted to NVC. You will receive a confirmation. Check their status here:

Consular Electronic Application Center (state.gov)

You have to submit documents to NVC within ONE year ususlly. Contact NVC if not clear. NVC responses to emails.

2. Your sister will register on CGI to select how they will get their passports back.

3. They will then bring all civil documents (original versions) and other items to attend interview as schedulled by NVC in Guangzhou.

不是你自己什么时候去的问题。 Just do as NVC's instructions.