You normally build a mainform and subforms in a one-to-many relationship. The
mainform is the one side, the sub the many side, ie., one customer, many
accounts. Each sub needs to be linked to the main by something common to
both, like an ID. You could build the sub and "drop" it onto the main, but it
is easier to let the subform wizard build and insert it for you using the
link you choose.