After you select mono aux there are 2 boxes below that default to 1 thru 1, meaning you only want to assign one output on the AR. Just touch the 1 in the left box and rotate the controller to 4 and apply. If you want to have aux 1-4 on the first 4 outputs on the 3rd row, start with the lower left out out, select mono aux, the highlight the right box, rotate to 4 so it reads 1in the left box 4 in the right box, then apply and it you will have aux’s 1-4 on the bottom row of outputs. Same idea works in assigning inputs & assigning other routing from the console.