How can i make this kill all players on start?

I tried making a script that should kill all players on start but it does not work. Here's the code (note that i am a beginner scripter) :

local Players = game:GetService("Players")

game.Players.PlayerAdded:connect(function(player)
print(player)
local pname = player.Name
wait(4)
local homanuid = game.workspace..player.Name
local hooman = homanuid:FindFirstChild("Humanoid")
repeat until hooman.Health == 0
hooman.Health = -10
wait(0.2)
end)

What's wrong? And the error is "attempt to concatenate field 'workspace' (a userdata value)" on line 7.

First of all, you only need one . to access the children of an object. Also, you can use the keyword workspace rather than game.Workspace (note the capital W when using game. in front!). Finally, you can get the character by doing player.Character instead.

I'm not sure what's with your variable names but I won't judge:

local Players = game:GetService("Players")

-- capital C for Connect! lowercase version is deprecated
game.Players.PlayerAdded:Connect(function(player) 
	print(player)
	wait(4)
	local homanuid = player.Character -- better way to access character
	local hooman = homanuid:FindFirstChild("Humanoid")
	repeat 
		hooman.Health = -10
		wait(0.2)
	until hooman.Health == 0
end)

Hope this helps! :)