Here's something I had trouble with earlier so I thought I'd write up a guide on it.
1. Go to actions. (The cog in an orange box.)
2. Choose ask player for a variables name.
3. In the variables name box type in the word you want.
4. In the box underneath choose what your "password" is.
5. If it's supposed to be an actual password and not a word you just type in and enter click the box next to "password mode." There should be a tick in it now.
6.Set the next message to 1 in the wait timer box.
7. In this boxes actions menu choose read a variables value.
8. Type in the variables name into both boxes.( make sure they're both identical.)
9. congratulations, you're now done.