Ruby on Rails

I haven't been able to get jquery datetimepicker working so referring to another app where it does work i found the file app/assets/javascripts/package.json in the app that worked In the file a bunch of settings for jquery  datetimepicker shown below From there i searched the web for package.json and found it's a file created by either yarn or npm so then I see there's instructions to install jquery datetimepicker via npm or yarn Trying to install by yarn caused yarn to hang, it doesn't return a prompt but npm installs it quickly creating package.json under /node_modules but datetimepicker still doesn't work That's a different directory than the app I found the package.json file in that has datetimepicker working so I must have installed it for that app using yarn Anyone can advise please