I have only had ducks for about 5 years, and the first year I had a hatch I didn't do anything and the mother took care of it all.The only thing I had to do was rig a chickenwire "ladder" into their swimming pool so they could climb out since they were too little to use their wings to push themselves up and over the edge. The next year the same mother would hatch the ducklings and then kick them out of the nest for some reason--found two perfectly hatched ducklings dead in a corner of the pen that way. Don't know if she killed them or if they died and she was just "cleaning house". One of those my son actually revived and it grew to adulthood (I still have him) but he has an oil glad issue where he can't clean his feathers--maybe that's why she kicked him out, because she could tell something was wrong.
So for the most part, their instincts should kick in and they can do it all themselves, just need a little help with swimming water (had a couple die that couldn't get out of the water, even when it was a shallow pool--placing a brick on the inside edge seemed to help with this) and having "chick feed" that is smaller and easier for them to eat than normal pellet food
Hope this helps!