As mbc says, don't try to over-manage. They'll move into a super and relocate stores upwards in time - if they have the oomff to build well into the second brood box.

Yes, bees work upwards when you give them space up there. Once they have accepted the space as useful. Then as they fill it with stores (at this time of year) they work out the way and down. Their aim is to have stores over their heads and elsewhere where there is space not needed for other purposes.