Hope you enjoy your new allotment.
There is no need to turn/weed. Although many fellow allotmenteers will tell you to do so. You probably dont even need the polythene. I have just put down a layer of card in my new greenhouse with about 3 inches of well rotted manure. this will significantly weaken the weeds and I just make sure that I go round each week and lift out any weeds that are cheeky enough to put their heads up.