How best to grow from seed/fruit? Heard ez. Ez if you know how. Aren't there a lot of these in LA?
There is a lot of variety in these plants. First you have to find a tree with the type of fruit you wish to eat. Then you plant seeds from that plant.
If you need a good seedling you could try papaya tree nursery who sell Big Jim and Japanese Supersweet varieties. If you need more direction find information from the Southern California rare fruit growers!