Audio from Mackie audio board to ATEM SDI Pro ISO

Using the following, but not sure how to get the audio set up correctly.

3x PTZOptics Move 4K 20x
1x Mackie 3204VLZ4
1x ATEM SDI Pro ISO

Video via SDI from PTZOptics to ATEM = no problem.

I'm having difficulty getting audio from the Mackie to the ATEM Mic1 input.

Which Mackie output should I use? Is there a specific cable I should use to make the Mackie to ATEM connection?

use LEFT and RIGHT lines (TRS) with cable 2x monoTRS to 1x stereo 3.5" TRS ..