Writing program to update Infocube in BIW

Hi,

I am a ABAP Developer and pretty new to BIW programming. I need to write a program which reads the data from Info cube and updates the info cube. Please help me what commands do I need to use to to read data from Info Cube and Insert data into Info Cube. And also do I need to write the program in SE38 or SE37. And also please provide me one example program, this would be great help to me.