minimize coulman in alv

i have a report in alv. my alv is very basic and i wont to decrease the size of two coulman in my alv . i copy the code from se 83 basic alv grid in the main program. i copy ,pbo ,pai screen 100 ,gui status ,in the pbo i give the name of the structre and changinig i write itab ,my table with fields . i build a structre with all the fields i wont to display . please write my detailed solution becouse i new with alv.

thanks.