If you search it, you will find it.
More or less, make a 1.030 DME solution, drink two Orvals, add the dregs to the DME solution. Wait for it to get going. Step it up to make a full strength starter. Pitch it into your fresh clone wort. Give it about 6 months before bottling so the Brett can do all it's work.
I'm planning on using Orval yeast in a beer, but not a clone. I haven't quite settled on what yet.
The only thing worse than someone who whistles a tune is someone who whistles tunelessly.