Custom FPM Form form Development

Hi Experts,

I'm new to HCM forms and i got requirement to create a Custom form as FPM Form.

I have read threads from scn and i got bit infomation to develop my form by using HRASR_DT Tool. Here my confusion is How to connect my form with Feeder class and where to write the business logic because i have lot of fields to design form like below images. For this i have created one structure for all the fields on the form.

Can any one Help me to build custom form with business logic( Where to write code and how to link with form).

Thanks

Venkat