The seed can be extracted from the fruit at any time after it is ripe. Older fruit may give quicker germination. Remove the seeds and wash thoroughly. Then wash them a couple more times! Even tiny amounts of chemicals from the pulp inhibit germination. The seeds are quite large and have tough coats. You might want to try nicking them or scratching with dandpaper. Germination is slow and erratic. Fluctuating temperatures including freezing, and fluctuating dry and wet periods, all help to germinate slow seed. I've had good results germiating in a wet paper towel at room temperature.