There are literally so many ways that one can do the activities,
Here is just one suggestion.
Day 1 - 1pm arrive / 3.30pm Helicopter flight / 4.30 pm Sunset cruise and dinner cruise
Day 2 - 6am game drive Zambezi national park / 2pm tour of the Falls
Day 3 - 6am Elephant back safari.
It would be far better to send us a booking enquiry form and we can then arrange a specific intineray suited to your needs. I dont know where you are staying or when you are leaving, so really a bit impossible to give you proper advice. There is a big difference between staying on the Zim and Zambian sides and this needs to be taken into account