Machine Learning: Create model from Apple Watch data (accelerometer and gyroscope)

Hello everybody,

I have very little experience developing applications for the Apple Watch. I want to use the Apple Watch to capture accelerometer and gyroscope data to create a CoreML model.

Could you give me some pointers on what I would have to do to be able to gather the data I need from the Apple Watch?

Do I need to create a simple Watch app to gather this data first and save it to a txt file, for exemple?

Thank you for your help.

Best regards,
Tomás