How do I use ODK Sensors in my under developement Android App?

Hi everyone, the title of this topic is pretty self-explanatory:

since I realized that ODK Sensors only comes in the form of a .apk file,
I’m trying to understand how to use it in my Android App, which needs to
read data from a sensor via usb and bluetooth bridge. Should I invoke and
run the apk procedurally from my code? I am not sure I got this right.

Also, where could I find some documentation regarding the methods to invoke
when using the framework?

Thanks in advance,