So i have this error: Error while compiling: AdminMode.cs(39,46): error CS1503: Argument `#1' cannot convert `BasePlayer' expression to type `string'
and i have no idea how to fix that.

if(permission.UserHasPermission(player, "AdminMode.use")) //Error Part

Just had to change

if(permission.UserHasPermission(player, "AdminMode.use"))​

To

if (permission.UserHasPermission(player.userID.ToString(), "AdminMode.use"))

It would be even better if you instead did

if (permission.UserHasPermission(player.UserIDString, "AdminMode.use")​)

This would mean you don't have to cast the ID to a string.

Yea, thank you very much!