Help

Im new here, so forgive me if I'm in the wrong forum, but uhm
I just got Pokemon Platinum, and my DS download doesn't work...actually DS download doesn't work for all my games. ???
also, I heard WiFi works, but does that mean I can still trade and battle other people around the world? I've never used Wifi before, and I was wondering since DS download doesn't work, so I'm kind of skeptical about Wifi.

Only some games support DS Download Play. And I do not believe the Pokemon games do.

Pokemon games no. They each need their own copy.