If you don't have a specific Meta key (which is highly likely - in 10 years or
so of using Emacs on various systems, I have never seen a key labelled Meta!),
you can use Esc instead. On a PC this is the Esc key, and presumably the same on
the DEC keyboard. The difference between using Meta and Esc is that you would
need to hold down the Meta key and press the other key to get the sequence,
whereas you press and release Esc before pressing the other key for the key

Hope this helps (although it may be I am not actually answering the question!).