The water is from the defrosting of the coils in the freezer.

Usually it runs down a tube on the back of the fridge.

There are 2 ways that it can get into the tube. I cannot tell which yours uses by looking at the parts diagrams.
1. Directly from the freezer out the back.
2. It drips into a funnel like part at the top back of the fresh food and then out the back to the tube.

First I would check at the bottom end/drip tray to be sure it is not clogged here with dust etc.
If OK
Then you will have to blow it clean from the top.
A compressor on low pressure works, using a straw and blowing into it works depending if you can get a decent seal or a turkey baster and somer warm water.

Once clear it is a good idea to flush it withla 10% bleach solution here is where the baster is really handy. This will kill/flush out the crud growing in it. Just watch that you do not overfill the drip tray.

While you are messing with it you might as well clean the condenser coils and fan blade under the unit.

I have seen it suggested but have never tried the following.

To keep the drain from freezing take a piece of bare copper 12 gauge wire and wrap it around the defrost heater once or twice and then down the drain an inch or so.
The idea is that every defrost cycle the wire will also defrost the drain.
Cannot see why it would not work and have seen people who seem to know their fridges pretty well suggest it.
Only concern I would have is the wire getting too hot during defrost.