This is a difficult question to give an exact answer to as the amount to feed will depend on how many fish you have, how big they are, what the water temperature is, when they were last fed etc.
However the golden rule of feeding them 2–3 times a day on as much as they will eat within 5 minutes is a good one to follow. This will certainly change throughout the season. In cold weather the quantity the fish will eat in 5 minutes may be as little as 2 or 3 food sticks, whereas at a pleasant summer temperature of 20oC the same fish may eat several handfuls of food.
The amount you feed to your fish may not seem very much, but remember that food sticks or flakes are only 8% water, whereas the natural food your fish will eat (algae, insects, shrimps etc) is over 80% water. So the dried foods are 10 times more concentrated.
When feeding your fish, you don’t want them to lose interest and there still be food on the water surface. Any uneaten food can decompose and pollute the water. As a result it is best to err on the side of underfeeding.
Once your fish have settled in your pond, they will quickly learn to rise to the surface every time you go near. Don’t be tempted to feed them just because they do this, they don’t need any more food! If you wish to, you can replace the 2 – 3 feeds with more frequent feeding, but still follow the 5 minute rule and make sure everything is eagerly consumed – they will eat less at each meal.