Go and talk to your course tutor.
You sound very confused about how to write an essay and as this is actually a pretty simple one, you clearly need some help. Its okay to ask for help btw - you arent expected to *know* exactly how to do this when you arrive at Uni.
Struggling, getting frustrated and feeling inadequate can be really demoralising and upsetting, so go and talk to your tutor - its what they are there for.