Designing policies is little serious job. This is because policies have organisation-wide implications. Further these need to be customised to your company's requirement. Against this backdrop, how come that "senior" manager has delegated this work to a fresher like you is not understood.
The first test of managership lies in understanding what to delegate, to whom to delegate and how much to delegate.
If you search this forum, you will get ample policies, but then to decide what is useful and what is not useful, I recommend you leaving it to your "senior" manager.
As rightly mentioned by Dinesh ,policy formation is a difficult task . But since it has been sssigned to you , take it heas on . to help you may include some of the following in your handbook.
1. Introduction to employee policy handbook
a. Purpose and scope
2. Introduction to organization:
a. Company Mission
b. Company History
2. Employment ethics and conduct
a. Dress and grooming
b. Non disclosure and Confidentiality
c. Ethical Business practices
d. Personal behavior at workplace
e. Use of mobile, internet, Laptop and data card
f. Fraud, embezzlement, dishonesty in transaction
g. Disciplinary action
4. Performance Management System
5. Working conditions
6. Transfer and deputation
7. Local/domestic travel
8. Learning and development
10. Grievances handling
11. Harassment free workplace
12. Employment of relatives