It seems that sometimes lately it is taking 4-8 weeks for USCIS to send approved I-129Fs to the NVC. You will know it's been sent when the I-129F case status changes to "Case Was Sent To The Department of State". Once NVC processes it they will send it to the embassy that will do the interview. At that point, the petitioner will receive an email with a "K1-FTP" letter attached that will have your DoS case number and the date it was sent to your home country's embassy. A few weeks after the USCIS status changes to sent to DoS, you can start making inquiries using the NVC's online inquiry form to get your DoS case number. Once you get that, you can track its status on CEAC.
I will make a suggestion that when you do start making requests on the public inquiry form for NVC, include a scan of your NOA2 in the attachment section and on your first inquiry, after you request your case number say something like, “Please also update the petitioner and beneficiary email addresses as follows:” and give both your email addresses to them. Sometimes when they input the case information from the I-129F, the email addresses get messed up. Jaycel and I did this on our first inquiry and after that we got every email from NVC and the Embassy sent to us without any trouble.