How to wire system - Integrated amp for speakers with external X over (Apogee Minigrand)

I am trying to use an integrated amplifier to drive a pair of speakers and sub (non active) that has an external cross over unit. The manual only provides direction using preamp and power amp setup where the cross over sits between both of them.

I simply need to know how to use an integrated amp since I do not wish to go with the pre power route. 
Would truly appreciate your advise before I seek directions from Apogee users. Thanks