Question
Do you break the new plant off a spike or cut it in some way? Do you put the new roots all the way under the potting mix? As you can tell I have never done this before.

Answer
New plants that are found on a flower spike must grow fairly large (ie 3 inch + leaf span + new roots) before being removed and potted up on their own.  Separate the new plant at the point where it is attached to the old flower spike by making a cut there with a sterile razor blade.  You may pot the new plant up in fresh orchid potting mix so the roots are into the mix and the leaves on top. The larger the new plant is at time of separation, the more successful the separation and potting will be.