Push three cocktail sticks into it. Suspend it over a glass of water so that the water covers a couple of centimetres of the stone. Put it somewhere warm out of direct sun .The roots will take a while to appear ..about six weeks ..then you can pot it on .Alternatively put it in a pot of compost with the pointy end sticking up. Cover the pot with a plastic bag and put it in a warm dark place..when the shoots appear bring it into the light
They take a while to germinate so you need some patience .they won't fruit in our climate though ! But you can get a nice plant from them.
my father used to dry the stone out for a few weeks, then soak it in water overnight and put into a pot of soil. they used to grow to about a foot then wilt and die, probably needed putting into a hot green house and nurturing.
alf.