How would I get chat messages to pop up randomly?

I'd like multiple messages to pop up randomly on the roblox chat GUI not sure how to do this can anyone help?

Resource(s) Used In My Answer: SetCore - Roblox Wiki

Answer to Your Question: You're going to want to start by creating a localscript inside of StarterPack. This is how we can access SetCore, which is part of the StarterGui. Here's your script:

math.randomseed(tick()*wait()) -- This ensures random numbers, and is used for math.random() later on.
local messagesToDisplay = { -- Inserts messages into here
	"[GAME]: Remember to thumbs up the game!",
	"[GAME]: Remember to favorite the game!"
};

local minTimeToWait = 60 -- What's the minimum wait time?
local maxTimeToWait = 300 -- What's the maximum wait time?

while wait(math.random(minTimeToWait, maxTimeToWait)) do
	local randomText = messagesToDisplay[math.random(1,#messagesToDisplay)] -- We'll get a random number between 1 and the total of all messages in the table and use that to find a random message.
		game.StarterGui:SetCore("ChatMakeSystemMessage", {
			Text = "randomText!"; -- Required. Has to be a string!
			Color = Color3.new(0, 1, 1); -- Cyan is (0, 255 / 255, 255 / 255). Optional, defaults to white: Color3.new(255 / 255, 255 / 255, 243 / 255)
			Font = Enum.Font.SourceSans; -- Optional, defaults to Enum.Font.SourceSansBold
			FontSize = Enum.FontSize.Size24; -- Optional, defaults to Enum.FontSize.Size18
		})
	end
end

Conclusion: Using math.random(), SetCore, and other important Lua/RBXLua features you can create a script that will randomly put out a message to the player every 60 - 300 seconds (obviously the numbers can be changed). I hope I helped you! :)