How to get a script to get a players name into a text box, Screen gui?

So I have a script which when you enter displays a GUI, but how do I get it to display a custom message depending on your name, and then the name appears after "Hello (PLAYERNAMEHERE), welcome to...."

local playername = game.Players.NewPlayer
local admin1 = game.Players.Lukeb50
local admin2 = game.Players.SickAtHackers

function NewPlayer(Player)
	if NewPlayer == admin1 or admin2 then
			script.Parent.Text = "Hello (playername), you are an admin. Please say :help for the commands"
	end
	script.Parent.Text = "Hello (playername),Welcome to Vault-Tec Vault 111"

end