You can make a table or a list of players you want to kick.
This works by getting their username, but you can do it with UserIds as well.
local Players = game:GetService("Players")
local YourList = {"Example", "Example2"}
function OnPlayerAdded(Player)
if table.find(YourList, Player) then
Player:Kick()
end
end
Players.PlayerAdded:Connect(OnPlayerAdded)
Not sure if you have to put table.find(YourList, Player.Name) or just Player lol. Think they both work.