How do I make a script when a player types a command it gives them a back accessory?

Hello!

I was wondering if there was a possible way I could make a script that when a player types a command such as !sword, it uses the id of the item sword that I picked then applies it to the players back.

I tried this, it has worked with Faces, Legs but I haven't found out how to use it or a new method for back accessories.

local Command = "!sword"
game.Players.PlayerAdded:Connect(function(player)
    player.CharacterAdded:Connect(function(chr)
        player.Chatted:Connect(function(msg)
            local Humanoid = chr:WaitForChild("Humanoid")
            local Desc = Humanoid:GetAppliedDescription()
            Desc.UpperTorso= 1678356850-- sword
            -- IF command match start --
            if msg:sub(1, Command:len()):lower() == Command:lower() then
                Humanoid:ApplyDescription(Desc) 
            end

        end)
    end)
end)

Asking for help!

Thanks! -xJTv