i created in eclipse a prg file and put on the device on apps folder : the widget works but from the mobile app i can't see any settings option. Any advice ?
Side loaded applications don't support the use of settings but only a static set of settings in the application or manually copied settings file. You'll want to look into the app stores developer only feature outlined in the developer blog here (https://developer.garmin.com/index.php/blog/post/connect-iq-beta-apps) and I believe there are some posts in the forum about it.
In order to use settings through the connect mobile app you have to upload the app to the store. If you don't want to publish the app publicly, you can use the beta option presented when uploading the app initially.
It's been awhile since I've done this. You run your app in the sim, set things the way you want, then use the .st from the sim's temp directory to your device, making sure the case and name match the case and name of your sideload
Nowdays I usually just set my app as a beta app in the store
