use the command "/lg" to open a GUI that will let you up your stats. the first time you up a stat it will cost you 1 level. the second time 2 level, the third time 3 level... the one thousand five hundred and sixty seven time it will cost you 1567 levels! you can upgrade this followin stats:
-Max Health
-knockback resistance
-Armor
-luck (for fishing)
-walkspeed
-mining speed
-attack damage
-attack speed

This is my first plugin btw, tell me if I did anything wrong!