To pull off the OTK, you should have one Radiant Elemental, one Mind Blast or one Shadow Visions, and six Shadow Reflection. You can have one less Shadow Reflection if you're holding another Radiant Elemental and you can have one less Shadow Reflection if you're holding another Mind Blast or Shadow Visions.
Mulligan away any card in favor of Radiant Elemental as you're basically dead in the water without it and as long as you draw any of your other cards that aren't Shadow Reflection you can dig for your Mind Blast.
You'll be mostly idle for the first few turns or so. Hero power your face as needed and wait to draw your combo. Play two Radiant Elemental and then rain six free Mind Blast down on your opponent using the copies generated by Shadow Reflection. Use Shadow Visions to dig for Mind Blast if you don't already have it.
Power Word: Shield can be used on enemy minions to dig for your combo pieces. Or, if you've already got your Radiant Elemental down, it can be used to infinitely dig through your deck to find the other cards you need. Just make sure you have enough Shadow Reflection to deal lethal damage!
Easy peasy. Enjoy!