If you are learning a new piece of software, errors can cause you the geatest amount of frustration of. Relax. It does not get any better as you go on. You stop making "simple" errors and make more "subtle" ones as you gain experience.
All is not lost, though. Locating and using reference sources on the new software is an effective way of dealing with the frustration and channelling you anger to get positive results. For ENGR211, you have the following text resources:
The commands help and
doc get you to various sources on MATLAB use that are
attached to the computer (or network) you are connected to. Use them.