How do you display a message on first play of a game?

I need to show an instruction on the first time the player plays a level but then not show it the next time the level is loaded. Any ideas?

Since the player may quit and come back, I’m assuming you wouldn’t want to show the message the next time they start your game. You’ll want to check out PlayerPrefs:

http://docs.unity3d.com/Documentation/ScriptReference/PlayerPrefs.html

So when you start your scene, check PlayerPrefs for your flag to determine whether you’ve shown the message. If it’s not present, show the message, stow the flag in PlayerPrefs and go on. Once stowed, subsequent executions will see the flag and skip the message.

Just set a bool using the PlayerPrefs class.

The information carries past the application’s lifetime when using this class (it creates another file to hold the information you set with it).

A note though that this class flushes the variables to the file (ie. writes them) every time you call it, so if you want to write more data at once, you may wish to look into this version: Writing PlayerPrefs, Fast - PreviewLabs. Or you can look into serialization (XML or binary).