Things i would like to know remember for my place not my profile:
How to get them in your game in the first place
How to give them away(When they join, get a kill, make it fall from the sky, ext.)
How to make a leader board at the bottom
1) You earn them from in-game sales.
2) You'd use this line with a bunch of more lines to how you want your points to be distributed:
game:GetService("PointsService"):AwardPoints(player.userid, 1) --1 Is the amount of points given.
3) A leaderboard is feature at the bottom of the page when points have been awarded to players in your game. They only work for player points.