Here's one of the approaches you can think of. You may also divide it into multiple methods, with each method doing a specific task.
1. Get employee name as user input.
2. Assuming, the data in the file is consistent across all the lines, find the user entered name in any line. Lets call it as findEmployee().
3. check if there exists a line in which the user entered name was found - lets call it as exists()
4. if the employee name is found, print it into the console as you are doing for all the employees in a do while loop. lets call this method as printEmployee()
5. if not found, print a message.
An alternative approach (if the whole file can be loaded and stored in memory and you are planning on looking up multiple names) would be to read in the file, store the details of each employee in instances of an Employee class and then store the instances in a Map keyed on the user name.