How to record guitar with a contact microphone?

I am trying to figure out how to record a guitar with a contact mic on it, with my iPhone. The contact mic has a 1/4 inch female audio jack, so I had to connect it to a 1/4 inch male to 3.5mm female mini-jack converter. Then a 3.5mm male-to-male 12 ft TRRS (3-band, 4-conductor) cable, which is connected to a headphone/mic TRRS 4-pole Y adapter which is plugged into the headphone jack of my iPhone.

So basically: Contact mic -> audio-to-mini cable -> mini extender cable -> Y-adapter's mic jack (my headphones are plugged into the Y-adapter's other jack) -> iPhone.

This doesn't work. The app is still just using the iPhone's internal mic.

Having a hard time figuring out what cable(s), or maybe what app, I need here.

Thanks