Employee Left company without serve notice period - How do we recover damages/losses of the company?

Hello All, One our employee left a company without serve notice period. So, How do we recover damages/losses of the company?
What should I need to mention in Appointment letter where we can avoid that kind of situation in future?
Please send me a format of appointment letter or bond letter related to a notice period. Thanks a lot in advance.

What are the losses/damages incurred by the employee as employee left without any notice period?

like project deadline. It's IT company