Hello! This appears to be a written and graded assignment. While we cannot write assignments for you (trust me, I've been there, and gotten my question deleted, whoops), we can provide information to help.
A random sample is a selection of absolute chance; in other words, there is no way to predict the individuals or objects being chosen. By chance, put simply.
For example, if I wanted to create a survey on sports played by 100 different people, I would randomly select 100 students from a high school. That way, the chances of there being unbiased answers is better. It would not be a good idea to do this at, say, a soccer field because the results are likely to be biased (all soccer players). It is predictable and does not give a fair chance.
I hope this helped! Best of luck on your assignment!