I need advice from a scientific POV on achieving sleeping in"Buddha pose",upright cross legged, and in a polypshasic format(2 to 4 hours per 24 hour cycle)

How do I fall asleep the first weeks? It's hard to sleep upright!should I do an all night vigil so I sleep automatically ?

Will taking melatonin hurt or help polypshasic sleep?

How Will this impact my REM sleep and my (lucid?) dreaming?