Does anyone here happen to know how to code a smartwatch app?

Question

If you have a Garmin watch you might have seen the Connect IQ where you download apps on your watch, but you can also code one.
Could someone please tell me how to start to code an app and what language/s I would need to know?

Answer 1

What OS does it use?
Does it use android wear?(wear OS)

Answer 2

I’m not sure.
I found out that Garmin uses the Monkey C coding language though.