According to the instructions, you should wear your bra on the loosest hook first; pull your breasts up into the cups; and then as time goes on, tighten the straps.
The idea is that as time goes on, and you continue to wear your bra, the straps and hooks stretch out. By moving from loosest hook to tightest hook over time, you ensure a snug fit.
There was consoling...
And some shared their favorite bra-sizing tips.