What does it mean that the dental clinic requires nurses to be on duty for a week?

After recruiting new people, the company requires them to have a probation period. Probation period is the time range set aside by the unit to assess whether employees are suitable for promotion, but it is not included in the labor contract and there is no salary. During the probation period, even if the enterprise dismisses employees, it does not need negative compensation, but during the probation period, the enterprise needs to pay compensation.