In BW, the data loading to infocube or any multiprovider will be follows like this..
Creating Info_Package--> Data Source--> PSA--> DTP--->InfoCube.
in Data Source section, BW guys will create table for pre-coming data. as a BODS person it's our duty to make a table exactly like the table that has been created in Data Source as source and loading into target table which is presented in Data Source.
that's how it works.