Noise when you turn is normal, its just the nature of the hydrostatic drive system. Its like a squeal, hard to describe but they all make noise. If its a grinding or clunking sound, then be worried.
To check the level, assuming its the same setup as other modern machines, there should be a bolt at the front of the chain case where the lift arms sit. You use a 1/2" drive bar to un-do it, when the machine is on level ground oil should be level with the threads or be felt with your finger.