How do I add a specific code to a game?

I want to add a certain code that when entered plays a secret sound and takes you to a secret level, but I'm not too certain on how to do that. I used a text input box but I'm thinking of changing it to a 9 digit code panel. I just need the correct code put in for it to work.

A straightforward (but boring) way to do it is to make 9 textinputs (ti1, ti2,..) next to each other. Then put their value in one variable like: Set Variable code to ti1.Text & ti2.Text & ...

Then you can check if code = the code you are looking for.