as an employer i wish to see the private browsing sessions made by a member of my staff. How do i do this?

Private browsing history is not saved on the PC. That's the whole point. Your company firewall (or proxy server, if you use one) may generate and store logs of all employees' browsing sessions. In some cases, the firewall stores only general information and you need to set up a log capturing server to store the detail. You may need log analysis software extract the one employee's requests (e.g., using the employee's PC's IP address) from the detailed data. Before viewing the data, I suggest you check with your HR or legal department to avoid violating any privacy terms in your employment agreements and/or employee handbook.