table control

Hi group,

I created table control (with wizard) to display custom table data with insert delete buttons, when user wants to add new entry after pressing insert button I need to auto populate code by checking table I need to increase previous value , can any body suggest where I can write this logic.

also when i am pressing insert button its allowing me to write on the first  row for example above ACC1 record , but I want to add records below ACC3 can any body suggest