Vanda orchids grow in huge cluster on top of a tall, sturdy stem. Although they are generally individually wired and placed in bouquets like cymbidiums (see this url below)
the photo you show suggests that the orchids were left on the original stems which are cleaned of any leaves. Cluster the flower heads close together and ribbon wrap down the stems.
This is one method. I generally wire and tape each individual bloom and then cluster together. This gives me much more control over the final look.
Be sure to spray throughly with a flower sealant to keep the blooms fresh for the day.
