How can I fill a grid using push button

Hi

I need to fill a grid with a button, first I fill 4 edit boxes and then I click on the button. the button makes an operation and must fill the grid, when the grid is complete I click in save.

This is my exercise.

This should be the result.

I am reading in internet but I cant find the solution

This is my peoplecode.

Local Rowset &RS_lv1;

&RS_lv1 = GetLevel0().GetRow(1).GetRowset(Scroll.CAP_PRESEST_TBL);

&prestamo_id = CAP_PRESEST_TBL.CAP_PRESTAMO_ID.Value;

&monto_prestamo = CAP_PRESEST_TBL.CAP_MONTO_PRESTAMO.Value;

&total_cuotas = CAP_PRESEST_TBL.CAP_CUOTAS.Value;