Been doing dance recitals for several years now and have always used on-cam mics and zoom H1N to capture ambient audio but I would like to record directly from the mixer to my zoom H1N as an alternative this year to see how it works.

I've done a lot of research on this but with my lack of knowledge in the audio field, I'm not making much progress.

The first thing I learned is that the Zoom H1N requires a mic-level input and that most mixers output at line-level. I proceeded to create a 50dB pad cable by taking a 1/8" stereo TRS extension cable, cutting off one end, and adding in some resistors and a new 1/4" male stereo TRS connector.

I was attempting to test this last night at the venue. They provided me an adaptor to connect my 1/4" TRS into an XLR output on their Yamaha M7CL mixer. The pad cable seemed to work okay as I was able to get a good recording, but it only came through as mono on the left channel.

Does anyone know how this should be done properly to get a stereo recording from the mixer to my Zoom H1N? The sound guy at the venue didn't really seem to know what he was doing and obviously I have no clue.

Actual stereo, or just feeding both channels (dual mono)?
The latter just needs the tip and ring of the 1/8" TRS plug tied together.
If it's a 'stereo mix' coming from the house board, there would be two lines, left and right. Typically the left channel is connected to the 1/8" TRS input plug's tip, right to ring. Of course BOTH would need attenuation for a mic level input.
FWIW, I think H1 has a line input.. although it would be unbalanced @ nominal -10dB , so 10-15dB of attenuation would be needed for feeding a +4dB signal.