Upload app to my personal watch without publishing

Hi,

Apologies if this has been asked before (I couldn't find any post).

How can I upload my app to my personal watch for testing? Do I need to publish it on the app store? I wouldn't like to do it, because I'm just starting, it's still a rough proof of concept.

Still, I need to run the app on my watch during my training runs, to get a feel of how it behaves...

Thanks,
JF