I want a gui button to give me a weapon?

so i tried this code to give me a weapon on press of the button and it didnt work

local player = game.Players.LocalPlayer -- Refer to the Player
local tool = game.ReplicatedStorage.Sword -- Refer to the Tool

script.Parent.MouseButton1Down:connect(function() -- When it's clicked
    if player:FindFirstChild("Backpack") then -- Not sure why I added this
        tool:Clone().Parent = player.Backpack -- Clone the tool to their inventory
    end -- End the if function
end) -- End the MouseButton1Down function 

You are cloning the tool with a LocalScript, but you can only clone with a server script, I believe. You'll have to use a RemoteEvent instead.

https://developer.roblox.com/en-us/api-reference/class/RemoteEvent

Example: (make sure you have a remoteevent inside of replicatedstorage)

button script:

local player = game.Players.LocalPlayer 

script.Parent.MouseButton1Down:connect(
    function()
        game.ReplicatedStorage.RemoteEvent:FireServer(player)
    end
)

backpack script inside of serverscriptservice:

game.ReplicatedStorage.RemoteEvent.OnServerEvent:Connect(
    function(player)
        local tool = game.ReplicatedStorage.Sword
        tool:Clone().Parent = player.Backpack
    end
)