add a new command for a "command block" or the "chat" which is '/scoreboard @p / @a "title for the board" {Top5MostKills} {Most [item]}{MostDeaths} {optional command use}

E . G . /scoreboard "jems" {Top5MostKills":"true} This will make a grayish box on the left of the player and will show: JEMS TOP 5 KILLERS: {name} [number of kills top 1] {name} [number of kills top 2] {name} [number of kills top 3] {name} [number of kills top 4] {name} [number of kills top 5]