Play back recorded tracksfrome Studio One 3 to SLAI AUx Sends while recording additional tracks at the same time?

I imported a song to Studio One 3 Pro. There are 26 tracks without drums. I need to record the drum tracks. How can I send the recorded tracks from the daw to my IEM's so I can listen and record new tracks at the same time?

My IEM (Shure P9HW) is patch into Aux Out 1 & 2, stereo linked on the SL14.4.2AI board.

I am stumped on how to assign the I/O's and/or create the busing. Can anyone assist?

I am a newbie at this so, pardon me if my terminology is not up to par...