How to make a popup GUI, Help if possible?

Okay, I've been trying to do this for a while. I'm able to do a click detector GUI but I can't do a popup GUI. I want it to be something at the bottom left that comes up and displays a message and then go backs down and comes back up displaying another message. I would like for each message to be scripted. If I can get any help on this I would be very appreciated.

Here's how to make a onclick function for GUIs.

script.Parent.MouseButton1Down:connect(function()
-- insert code here
end)

No problem.