Amp bolts directly to the bottom of the two speakers. The cable and white connector exit through a small opening on the narrow side (right hand side when viewed in Its installed position) where the two halves of the box are screwed together. The speakers connect via the flying leads from the amp - they should terminate in mini female spade connectors.
Obviously the box has to be split into its two halves. The speakers screwed into the top. The amp screwed to the speakers. The speakers connected to the amp. The two halves of the box screwed back together with the input cable placed correctly in the cut out so the white connector is on the outside of the box.