If the ice maker is defective or broken, it is unlikely that it can be repaired. The normal course is to replace it. This is definitely a DIY project.
Things to check:
1. Water connection, water valve, water source. Has someone turned the water source off? Is the water supply line kinked or crushed?
2. Is the ice maker turned on? Has someone inadvertently turned the ice maker off? Has the lift arm that turns the ice maker on and off been misaligned?
3. Is the wiring harness to the ice maker plugged in all the way? Has it come loose?
4. Check the water tray, is it aligned with the water source? Is there ice collecting in the bottom of the tray? Maybe the water is not hitting the tray, check to see that the water inlet supply is aligned properly.
If all of these things are working properly, then replace the ice maker. It is generally held on with two screws, loosen the screws and lift the ice maker off of them, be sure to carefully remove the wiring harness plug. Installation of the new Ice maker is just the reverse.