Rank beginner - advice on next steps with a phalenopsis?

[Blackbyrde]

Hello,

I am very new to orchids. I've only had a couple of hardware/grocery store phalenopsis, which I killed within a year. I have a new phalenopsis (again from the grocery store, one of the ones that comes with a plastic shotglass). I would like very much to keep this one healthy if it's possible, so I was hoping that if I posted some pictures here someone would be able to tell me what I can do to keep it going.

It just dropped the last of its blooms. I understand I should cut the flower spike about an inch from the base and dust it with cinnamon. Is that right? And do the roots look okay? It is putting out lots of little aerial roots, so I peeked at the roots that are down in the medium. They look a little grey, and there are more of them on one side than the other. There are also a couple of spots where they are peeking up at the top and they look a little brown. Overall I think it has the potential to be a healthy plant, but I really am afraid I will ruin it! I would very much appreciate any advice you could give me on the next steps to take with this one!

Thanks so much!