I found this in "Open Skies":

To connect from Terminal 3 to flights leaving from Terminal 2, proceed to Transfer Desk E in Terminal 1.

If connecting from Terminal 2 to Terminal 3, you will be greeted by Marhaba Services upon arrival into Dubai. A coach will be arranged to take you to Terminal 3 where you should proceed to Transfer Desk K to connect to your next flight.

A fee of USD 63 will be payable for all transfers between Terminals 2 and 3.

The minimum connecting time for inter-terminal transfers is 1 hour 15 minutes.