to work on push button

Dear all,

i have created a screen with pushbutton of display and next . when working on mara table in this screen when i enter material no and click dispaly it displays some features like ernam etc. i.e.i have programmed like that by case staatement and sy-ucomm but know my aim is to click next button and auotmatically get next material number details to be displayed . But i am not able top program for the same .I hope this description is sufficient enough to make you people understand my problem and help me out in solving problem