Mount your mounting plate to the CR-10 with 3mm screws (and washers if necessary).

Follow the official E3D Titan Aero build guide to build your Titan.

You may reuse the heater cartridge from the original HotEnd instead of the one in the Titan Aero package. This will save you soldering in the new one.

You may reuse the 40mm fan to cool the heatsink on the Titan Aero. This will save you soldering in the new one.

You will save the old active cooling centrifical fan. You can find a fan shroud that will mount it to your Titan Aero here.

You will want to reinforce the wires coming off the extruder carriage so that they don't droop onto the build plate while printing.

Disassemble the old extruder motor and take it off, it's just extra weight. You don't need the bowden tubing either.