New grower and a little bit confused

[Dess]

Hi,

I got my first Orchid, a Dendrobium Nobile, as a mother's day gift and I'm sooo excited and also afraid not to kill this one.

I'm also a little bit confused about the difference between the terms: keiki, new growth and spike.
Those at the base of the cane have got a couple of roots. I don't know how long they are as they are buried in the bark. Are these keiki's? What should I do with them?

The ones at the middle of the cane do not have roots. Are they gonna have roots eventually and what do I do with those?

In the second picture you can see where the flowers used to be. Should I remove these myself or just wait until they fall off. If yes, how should I remove them?

Please help? Can also anyone explain to me for once and for all what are keiki's, spikes and new growth?

By the way any other information that will help me no t o kill my orchid is more than welcome.

Thanks.
Dess.