Hi there, I need some help understanding the 95% confidence interval, a working out of how to or an explanation would be amazing!

Thank you

The human resources department of a very large organisation is trying to determine the proportion of all employees that are satisfied with their current position. They randomly select 100 employees and ask them: "Are you satisfied with your current position?" 68 replied yes they were. Construct a 95% confidence interval to estimate the true proportion of all employees at this workplace who were satisfied with their position. A 95% confidence interval for the true proportion of all employees at this workplace who were satisfied with their position is between (round your answers to 2 dp) and A researcher surveyed a random sample of 42 people who had been given the flu vaccine in 2017 and found that 24 did not contract the flu that year. A 95% confidence interval for the proportion of all people who have been vaccinated and did not contract the flu is between 0.422 and 0.721. Using the confidence interval can we make the following statement? The flu vaccine is effective (i.e. it prevents the flu) in 50% of those vaccinated. a