Pay Scale inrease - Custom Program

HI Guyz,

A custom program is developed for the pay scale increase and it should be run on a regular basis as a background job to update the pay increase of the employees who have completed either 60 days or 6 months or 9 months from the hire or rehire date. The program should perform the processing only for the hourly employees of the Personnel Area. The processing would consist of checking the current date with the employee hire or rehire date and determining the increase in amount based on the number of days the employee has been working. After the necessary processing is done the program will update new data records for the basic pay infotype for the associates who need to have an increase in the pay.

Can someone help me with the technical steps needed for this development.

Note:Pay Scale Reclassification program cannot be used as we are not implementing compensation management