Leaderboard Question

how do i make it so when a unit enters a regeon it subtracts 1 from the value on the leaderboard

Unit Enters Region (pick the region)

Conditions (unit is of type whatever) if you need it or owned by player, whatever you might need

Set Varible = to Arthmatic (varible - 1)

Update Leaderboard with Value (varible)

Ok, now how do i make it so when that variable gets to "0" it defeats players.

Just do an if then else statement. If variable = 0 then do defeat player, else do nothing. Easy as pie.