After paying IV fee, should I wait or submit materials?

[faminmao]

I'd paid $800 IV fee for my parents and had waited for a month but received no message from NVC since then. Should I wait for further notification from NVC or should I go directly to fill out the I-864 form and submit it with other relevant documents? (because I read a link prepared by this website's enthusiastic people that "do not take any action described without notification from the National Visa Center (NVC). Doing so could result in a delay in processing. ")

Please tell me what should I do. Normally how long I have to wait before receiving further instructions from NVC. Many thanks.

[immihelp]

What we have posted is correct. You should not take any action until are asked by NVC to do so.

[faminmao]

Thank you. Then approximately how long have to wait before receiving further notification?

[immihelp]

Wait times vary.

[faminmao]

Thank you Immihelp. I very appreciate your help.