It will be hard to describe all the rules of PF, ESI, Bonus & other things. I believe that your company is coming under "shops and establishment act Uttar-pradesh 1962".
Following are the suggestions for your query.
1) PF : Not applicable in your case as number of employees are less then 20.
2) ESIC : Applicable on Gross Salary. 1.75% Employees contribution & 4.75% employees contribution.
3) Bonus : Not applicable in your case as number of employees are less then 20.
For Appointment letter you can find 100 of formats available on this site . Just type your query on the "What Do you need?" box.
Hope this will help. Revert if your require more information.
All the best
9th March 2015 From India, Ahmedabad