How would I choose a string randomly out of a table?

You can use the math.random() mathematical function.

messages = {"Message1", "Message2", "Message3"}

RandomMessage = math.random(1, #messages)

script.Parent.Text = messages[RandomMessage]

Regarding the RandomMessage variable, it is just a number. The math.random() function picks a number from 1 to the length of messages, or 3.

In line 6, the Text property will display one of the message in the nth place of the array given from the RandomMessage variable. This script is assuming that it is within any scope for it to function as intended.

What you need to do is index the table using math.random

Because, when you index a table.. you use a number for the operator. If we use math.random, with a minimum of 1, and a maximum of the total number of indexes in the table then it will choose randomely from the table(:

Example;

local messages = {"Message1", "Message2", "Message3"}

local msg = messages[math.random(1,#messages)] --Get the random index

script.Parent.Text = msg --Set the text