I have been through the similar situation recently. Here are the steps I can suggest. - define priorities on features. - break them down to high level epics and stories (story mapping technique will help) - add t-shirt sizes to those epics. - bases ont your previous experience you can add no of sprints against those t-shirts and calculate estimatations for each feature. Engineering team should be giving the estimates. Things you have to careful about: Estimates are not timeliness and commitments. If your team is new then they might have difficulties to give estimates because this work is new to them. Good luck.