how can I find out where the water is coming from the bottom of regigerator?

All fridges and fridge freezer have have a mechanism for draining condensation. It is normally a small hole in the back of the fridge, often underneath the bottom shelf (often the veg crisper shelf). This drains to a tray at the back of the fridge where the water evaporates faster than condensation should drain. It sounds like either your tray is full or your drain is blocked in which case you would need to clean it out with a toothpick.

Neal
January 2008