Make a Field editable in webdynpro

Hi experts,

i have one webdynpro page ,which contains these 3 fields.

2 number fields and one date field....

2 number fields up to 2 decimal. Should be editable if user click on "modify" button. otherwise read-only.

Date field. Should always be read-only. once user click on the "save" button, this field should be automatically set to the current date (user or system).

can anybody please give the logic for modify action and save action....

Thanks& regards,

Praveena.