Hi i just tried to create one Multimain table session. In header when i give one item, In lines it should print all BOM item to that main items. Just like Bill of Material. Can anyone tell how Multimain table session will work? where to update lines , in header or lines session.

In this Case, You dont even have to create MMT. Just put the Main Item of the BOM as a View Field and create a Normal Multi Occ Session with View Field.As All the fields which you require are in one Table itself...