When you've got the Marshmallow update, the first thing is to configure Google Now on Tap. This is a long press one the home key rather than an upwards swipe (though I think it may always have been due to Samsung's hardware home key). If you don't want GNOT, you can opt out and the old Google app format will appear. However, check your location history and Google Photos sync settings if you've gone down that route. Refusing GNOT turned those off (I have web and app history off anyway).
