Can't transfer my .prg because my mac can't see my watch venu 3s

Hi, 

I started to code a new app for myself to track the score while playing padel but unfortunately my mac cannot see my device which is a Garmin Venu 3s. I tried many things but didn't found the solution. I think that I have to switch my watch to developer mode but I can't find out how to do that. 

Please I need some help :)