There is one thing you must do even before you start using your fridge: Do not plug your fridge into the wall outlet for 24 hours after you place the fridge where is going to be used. This is for oil inside the sealed system to settle down into the compressor in case the fridge was stored or transported or carried sidewise.
Once every two to five years you should clean condenser, which is located either underneath or behind the fridge. Make sure you use plastic brush, not a metal one.
If you see an ice buildup don't use sharp objects to chop off the ice. You can damage the evaporator that way. Unplug the fridge for 24 hours instead. Using hot water would make the problem even worse unless you expose the evaporator and melt all the ice and snow.
Every time you change the temperature wait 24 hours to see actual result.
Water filter should be replaced every 6 months or sooner - depends of how much water you use.