Editing text for textbutton doesn't show on the part, how do I fix this problem?

Howdy! You see, you indexed the value TextbuttonText to game.Workspace.SurfaceGui.TextButton.Text. That means, changing textbuttonText won't affect game.Workspace.SurfaceGui.TextButton.Text at all.

local textbuttontext = game.Workspace.SurfaceGui.TextButton.Text
textbuttontext = "e" --will change the variable textbuttontext
game.Workspace.SurfaceGui.TextButton.Text = "e" --will change textbutton's property, Text

Meaning, game.Workspace.SurfaceGui.TextButton.Text =/= textbuttonText.

A fix to this is to just:

local textbutton = game.Workspace.SurfaceGui.TextButton

while true do
    game.Workspace.Part2.BrickColor = BrickColor.new("Really black")
    game.Workspace.Part1.BrickColor = BrickColor.new("Really red")
    textbutton.Text = "Ready?" --textbutton dot Text
    wait(3)
    game.Workspace.Part1.BrickColor = BrickColor.new("Really black")
    game.Workspace.Part3.BrickColor = BrickColor.new("Neon orange")
    textbutton.Text= "Set?"
    wait(3)
    game.Workspace.Part3.BrickColor = BrickColor.new("Really black")
    game.Workspace.Part2.BrickColor = BrickColor.new("Bright green")
    textbutton.Text= "Go!"
    wait(3)
end

If you have any questions, ask them below in this answer's comment section.

local textbutton = workspace.SurfaceGui.TextButton -- using "workspace" instead of "game.Workspace" is much faster on typing time and slightly faster on indexing time

local p1 = workspace.Part1 local p2 = workspace.Part2 local p3 = workspace.Part3 -- index your parts before continuing with the script to save time, in some rare cases you will not need to do this (usually anti exploit or remaking an instance)

local waittime = 3 -- if you are using the same wait time for all three of the waits, create a variable so it is easier to edit

while true do
    textbutton.Visible = true -- if it is not showing up you may have an issue in another script or a different part of the code you are not showing me, fix it or use this to guarantee it shows up
    p2.BrickColor = BrickColor.new("Really black")
    p1.BrickColor = BrickColor.new("Really red")
    textbutton.Text = "Ready?"
    wait(waittime)
    p1.BrickColor = BrickColor.new("Really black")
    p3.BrickColor = BrickColor.new("Neon orange")
    ttextbutton.Text = "Set?"
    wait(waittime)
    p3.BrickColor = BrickColor.new("Really black")
    p2.BrickColor = BrickColor.new("Bright green")
    textbutton.Text = "Go!"
    wait(waittime)
end