If you have classes then you would know the difference in download, upload, and making an edit.
If this is a maintenance position then do the following:
If your that afraid, put the processor in local run mode where their is no chance that you could screw something up. Then get online with the processor. Best place to see what is happening with the program is to have a device layout and see where these devices are acted on in the program. Once you know what the program is doing when its acting normally then you would be in a better position to troubleshoot it when it breaks. Biggest problem I have with maintenance people is the only time they look at the program is when the machine is not operating correctly. Then they think something is wrong with the program and its really just some device has gone bad.
If this is a programming position then the company should have standard code or past programs to look at locally on your hard drive. Once you look at these then you can ask some informed questions.