Mapping in transformation

Hi

I replicated the DS into BW. But it is replicated as 3.x DS. So i just clicked on migrated and converted into 7 DS.

Now created the transfrmation on the cube and datasource. But here mapping b/w fields in DS and infoobjects in the cube didnt take place.

Do we need to do manually?

If manually how do we knwo to which field respective object to be mapped.

Regards

Annie