Get 6 ready to breed goldfishes, 2 males 4 females. seperate both sexes on different aquriums. Feed them nutritious meals, if you can provide live meals the better. After one week check the belly part of the female if it is already soft. If so, it's time to combine them with the males on the breeding tank. Add floating plants with long roots such as water lettuce and some jave moss to the tank. The next morning before sunlight check the tank for eggs. If you already got eggs remove all the parent goldfish. After a couple of days you will see wiggling fries. feed them with newly hatch brine shrimps.
GOOD LUCK!