How to open gui shop and teleport player when part is stepped on?

For whatever part you are touching add a script like this:

local Part = script.Parent

part.Touched:Connect(function(player)
    player.EDIT this to your gui opening
end)

I used to be confused by this too, the answer is simple though. By adding player in the function parenthesis you are adding a variable for whatever touches the part, a genius move by roblox if I say so myself. However, you will quickly notice that errors will pop up in the output tab but the script still works as it should. To get around this you need to have an if statement that asks if the variable player is actually a player, like this:

local Part = script.Parent

part.Touched:Connect(function(player)

    if player.Parent:FindFirstChild('Humanoid') then
        player.Edit This to Your Gui Opening
    end

end)

Any more questions? Just Comment!

-- WolfTamer894