Using the margin of error of 5% and confidence level of 95% , population size 14,000

Surveying students at a college.

(1) how many students will I need in my sample? Explain you answer.

(2) What are the trade-offs of going significantly over or under this number?

(3) In addition to sample size calculations, what are some other considerations regarding the sample that I need to make before sending out my survey?