Hot Water Heater Issues

I appreciate you information, and be patient with me, but the eletric element is why the electric part of the water heater won't work, and not to sound stupid, but does that also affect the propane heater, or does that have to do with the high limit switches???? I'm not really sure what the high limit switches are..... Also roughly how difficult is it to replace the electrical element???? Is it something I should bring it in to the repair shop??? Or can a person with average intelligence, and average mechanical knowledge handle it. Again Thanks a ton for the information.