Help. Difficulty with adding a new row

Hello, so I am working on a payroll excel sheet which pretty much tallies up the number of hours that each employee does bi-weekly. On my first worksheet, I have employees broken down by the sites they work at. I then have columns with their total hours worked for the month. I also have a total hours, how much PTO they have accrued and how much they have used. On the other worksheets, I have it broken down by month so that we can quickly see at any given time how much time they have worked and how much hours PTO they have accrued. I figured out how to input the data on the monthly spreadsheets and have those numbers mirror in the first worksheet. I have also linked the sheets so that they all have that employees list made on the first worksheet. However I have ran into a problem. When I go to add a new employee to one of the sites, it disrupts the worksheets. In this I mean that all of the numbers for meant for one employee would be shifted up one row. How do I add a new row for an employee without upsetting the data I already inputted for a different employee. Thanks in advance.