when does all the "christmas[xmas2] period" begin at disney? is it about nov?
Christmas starts before Thanksgiving and all the decorations, etc will be up before that time. That's 25 November this year.
Christmas generally lasts until the end of the week after New Year's Eve so plenty of time to catch them and they are spectacular.
Make sure you don't miss the Osborne family lights at Hollywood Studios - that gets bigger and better every year and they were up to 8 million lights some time ago now.
The actual Christmas Parade at Magic Kingdom and other Christmas events starts later though. I went to Magic Kingdom on December 14th last year hoping to see the Christmas parade and it was the ordinary parade, though I think they were doing the Christmas one for Mickeys Christmas party nights. The decorations were all up though.