The Requirement is a Database to support a Nurses Roster.
The Statement of Requirements defined by the User (Feerhaan from Mauritius) is as follows ...

To design a roster for 10 nurses working from sat to next fri on a 2 weeks basis(14 days).
The first 5 nurses work on the following schedule: 6 days + 2 nights +6 off.
The remaining other 5 will do the following schedule: 5 days + 3nights +6 off.
In addition each day 2 nurses must be on night duty - the remaining 3 nights will be covered by extra personnel.
A person cannot work consecutive weekends.

B. Things of Interest :-
B.1 Assignments
B.2 Nurses
B.3 Shifts
B.4 Etc

C. How are they related ?
C.1 Nurses are assigned to Shifts.