Theses are the steps I used in mounting my Haraella odorata,
Step 1
First choose your mount. You really can use just about anything. Many people and nurseries will use a wood shingle or splint. Personally, I find those esthetically unpleasing. I prefer more natural looking pieces of wood -- branches and such. But again, that's just the way my tastes run.
So here's what I chose to use
Step 2 (NOTE: Some people may skip step 2 depending upon the particular orchid and/or their growing conditions)
Next, you can make a pad of moist sphag. How much you need to use depends on the size of the orchid and just how much moisture you wish it to retain. I decided I wanted to experiment and instead of using sphag, elected to try coconut fiber. To that end, I cut a section out of one of the coco liners used for hanging pots and baskets. Because it is not as moldable as a handful of sphag would be, I tried to gauge about how large a peice I wanted to use. I put a couple slits in the pad -- one so it would fit better over a protrusion on the mount, and a second to slide around the base of the orchid.
Step 3
There are several options with this but it all deals with determining placement of the orchid onto the mount. Once you determine how you want the plant oriented, you can:
a) place the pad of sphag or fiber on the mount with the orchid's roots on top of the mount; or
b) place the orchid on the mount then cover the roots with the pad; or
c) put a pad on the mount, place the orchid on top of the pad, then put another pad on top of the roots
I generally do b) or c).
Step 4
Have a length of string, thread, fishing line, or whatever it is you plan on using to secure the plant to the mount cut and at the ready. (Most folks I know use fishing line. However, not only do I find fishing line to be a pain in the posterior to knot tightly, I also don't like the looks of it. Instead I use brown thread. Again, just my personal preference. I find it easier to work with and it blends in better. While nylon lasts longer, I figure by the time the thread degrades the plant will have rooted to the mount and the media I used will likely need replaced anyway.) Now we have reached the awkward part -- especially if you are doing this by yourself. With one hand you will be holding the plant and pad in place on the mount.
Step 5
With your other hand & as much help as your occupied hand can manage, tie the plant + pad firmly in place.
In this example, the plant's orientation was not quite as I wished. However, the plant was stubbornly refusing to cooperate to the degree I wanted it to. So we had to reach a compromise.
These are a few other mounts. Sorry for the blurriness -- especially on the Ang. dideri. The dideri is one I would like to remount. It was already attached to this splint of wood when I got it. Rather hate the thought of trying to peal its roots off the mount. As such I may just have to accept the way it is.