Just got a new house which has a pond and 4 goldfish in It which I know nothing about. There is a pump and waterfall. I have been putting the pump on every day in the morning and turning it off in the afternoon, not sure if this is correct also should the pump be put on during the winter or not.
Any help and advice would be much appreciated.

Thank you

Pumps provide two needs to fish, one is oxygen and the other is filtration. Oxygen and filtration are essential to fish, but especially goldfish, so you should leave your pump on 24/7 and it most definitely needs to stay on through the winter as any ice that may form over the pond will prevent oxygen from getting in and prevent toxic elements from escaping. I would suggest that you take a look at some sites that speak directly to overwintering ponds as there is a lot to know and some steps that need to be taken before any ice forms on the pond and before it gets so cold that you don't want to take on such a task.

Here are some helpful sites, however, I would disregard suggestions for adding products that claim to "neutralize" ammonia other than maybe Prime.
http://www.pondsolutions.com/over-wintering.htm
http://www.pond-doctor.co.uk/longoverwintering.html

A lot depends upon where you live. If you live in an area where you'll get a sheet of ice on the pond, then unplug the pump, sink it to the bottom of the pond, stop feeding the fish and put in a pond de-icer to keep a small hole open in the ice. A hole will allow valueable exchange of oxygen for the fish, and prevent the pond from freezing solid (if it's small).

Also you do not want to run the pump all winter as it will super cool the water and possibly freeze the waterfall solid and burn out the pump is you get harsh winters.

NOW, if you're in a place where you don't get awful winter weather, you can just keep that pump running 24/7. You really should not EVER turn off the pump during the warm weather as it depletes the oxygen in the water for the fish and can lead to disaster. So far you've been lucky, but as the fish grow, you will need to provide constant water flow in the pond.

I live in south GA, and I have my pump and filters running, unless the air temperature drops into the low 40s, simple because I don't want to cool the pond water down even more. It is usually a bit warmer than the air.