how do you evolve rotom evolve in platinum

Getting the Secret Key:
1) Activate the Mystery Gift through the Jubilife TV station
A) Go to the 3rd Floor and talk to TV Producer answering his questions as such
B) Opinion on TV: Everyone Happy
C) Feedback on TV: Wi-Fi Connection
D) Save your Game!
2) Go to the Mystery gift option on the start menu, while in a Wi-Fi accessible Hotspot
3) Select receive from Nintendo WFC
4) Go to Any Poke Mart and talk to the person at the edge of the counter
5) SAVE YOUR GAME!

Enter into the Eterna City Galactic HQ
On Floor 1, go to the Upper left, between the machine and the wall and press A
This will reveal a hidden room
Inside this room will be the appliances that Rotom can possess
With Rotom in your party, walk up to any and hit A
Rotom will possess the item and attempt to learn its specific move