Electronic voting is simple and so are the machines. Most voters who use them find them easy to use. From personal experience, when I voted using an electronic voting machine it was pretty cut and dry and simple. I did not have to ask any questions and I did not see any voters have any trouble using the machines.
Voting machines are not complicated things. For whatever reason there are people out there who lose any semblance of common sense or ability to read when confronted with a machine ballot instead of a paper one. Simply reading and following the instructions ensures a proper ballot is cast. It's not that hard.