How do I make a passcode script inside a gui that opens a frame if correct?

Before posting a question I suggest you learn the basics. This site is not a request site as well, though you are lucky that I will be helping.

Well if you don't have anything down then here are some steps;

1. Add a ScreenGui inside of PlayerGui
2. Make sure you have a TextBox inside of the new ScreenGui
3. Make sure you know what Frame you want to open and make sure it's named
4. Add a TextButton you can call it Submit, Enter whatever
5. Add a LocalScript Inside of the SubmitButton or EnterButton (the button you added)

1. Type in this code;

local code = 'YourCode' --This is the code the player has to enter
local SB = script.Parent --Submit Button
local F = --Add the location of the frame here
local Bar = script.Parent.Parent:WaitForChild('TextBox') --Change to correct name if you have one

SB.MouseButton1Down:Connect(function() --Fires when submit button is clicked
	if Bar.Text == code then --If the bar's text is the same as code 
		F.Visible = true --Make the frame visible
	else --If the code is anything else
		return --Returns and ends the code
	end
end)

Now I have explained what each line does so you should study them. If this helped then please click 'Accept Answer' below.