You don't
You buy them on an exchange.. even when this worked people weren't really mining them anyway, just exchanging computing power for premined coins.
Thank you for the reply. What about the other billions of XRP that have not been released yet? How will RippleLabs distribute them?
I don't know for sure but I would have to guess that they will end up selling them. They are not doing this for charity.
..There is a reason why they still own ~70% of the supply. (correct me if I am wrong, 30 billion are publicy traded, 70 billion are held by ripple labs)