Can I add Whatsapp and Google Hangouts to my Samsung Watch 3?

[bblondia]

I just purchased a Samsung Watch 3 but I don't seem to be able to get notifications from apps on my phone like Google Hangouts, Whatsapp or Gmail. My son calls me through hangouts and I want to be able to be notified on my watch when he does. I'd also like to get my Whatsapp messages to my watch as well.