Finally and congratulations! It seems like they didn't forget about you after all!
If you're doing consular processing (Applicant outside of the US), now you have to wait a few days for the case to move to the NVC. The USCIS case status will change from "Actively reviewing" to "Case Approved" and then to "Case sent to the department of state".
It should take about a week or so, maybe less but the NVC will email both the petitioner and the beneficiary with the log in details to the CEAC account, where you can file DS-260 and the affidavit of support!
Good luck on your next step!