Help diagnosing potential issue after replacing battery

Hello:

I recently tried to replace the battery in my 2015 Retina Macbook following this guide: Retina MacBook 2015 Battery Replacement, including doing the low-voltage charging step. However, even after more than 15 minutes of low-voltage charging, I am not getting the “chime” sound nor do I see the battery icon on the screen. I went back step by step and checked to make sure all cables were connected and screws were in the correct spots (confirmed) - however, the LED light on the logic board is not lighting up and does not respond when I push the battery disconnect button. (Not sure if this is diagnostic or not…) I haven’t turned the computer on given the warnings about damaging the logic board.

Any suggestions of things to try before do an uninstall and reinstall of the logic board?

Thanks so much!