[FFmpeg-user] Trying to merge and map 1 video file with 4 audio files

[Media Mouth]

We've have 1 video file, 4 audio files, all same length.
The video file is DNxHD36
The audio tracks are all .wav

The goal is to merge all 5 files in sync

Based on https://ffmpeg.org/ffmpeg.html#Advanced-options I tried the following:

ffmpeg \
-i 'Video.mxf' \
-i 'Audio1.wav' \
-i 'Audio2.wav' \
-i 'Audio3.wav' \
-i 'Audio4.wav' \
-c:v copy \
-c:a pcm_s24le \
-map 0:v:0 \
-map_channel 1.0.0 OUTPUT_CH0 \
-map_channel 2.0.0 OUTPUT_CH1 \
-map_channel 3.0.0 OUTPUT_CH2 \
-map_channel 4.0.0 OUTPUT_CH3 \
'/Volumes/ANF_VFX/prjx531-Xfers/ANF_103_230908_Soft Lock_MixStage_test.mxf'

Getting error
[NULL @ 0x7f814601a200] Unable to find a suitable output format for 'OUTPUT_CH0'
OUTPUT_CH0: Invalid argument

Also tried removing the extra 0 in the -map_channel lines,
	e.g. -map_channel 1.0 OUTPUT_CH0 instead of
		-map_channel 1.0.0 OUTPUT_CH0

Got error
Syntax error, mapchan usage: [file.stream.channel|-1][:syncfile:syncstream]