All StarterPack content will be copied to the player’s Backpack if I remember correctly.
So you should be able to access it by fetching the Parent twice.
However, the location of the script is not the best, it should instead be placed in the ServerScriptService and used RemoteEvents or RemoteFunctions.
Here the code will be duplicated for each client instead of being centralized in a single instance.
local Player = script.Parent.Parent
local Character = Player.Character
The above code should work.
However, the following capture clearly shows that when 2 clients connect, the code is duplicated. Which in my opinion isn’t best practice but will still work.