if you're using a microUSB phone, then it will be
phone -> micro-to-usbA(female) OTG -> usbA-to-usbC -> switch
if you're using a usbC phone, you can do
phone -> usbC-to-usbC -> switch
here is the OTG cable I've used in the past: https://www.amazon.com/UGREEN-Adapter-Samsung-Controller-Smartphone/dp/B00LN3LQKQ
If your cable doesn't have a micro-usb on one end and a
female usb-a on the other, then it's not the right one. Even if it does have those two ends, it may not be an OTG cable.
Then you can load up the NX-Loader app (
https://github.com/DavidBuchanan314/NXLoader/releases), select your payload. Then whenever you plug in the switch, your phone will prompt to send the payload (even if the app is not in the foreground). I used this video for reference when I was setting everything up myself (starting at about
4:35 for the android stuff):