If you’re testing your story in the app, you need to play through the chapter with the choice that has the gains and choose an outfit so you can gain that gain. Then play through the next chapter so you can test out the if/elif/else part. Of course, remember to reset story progress to test out the other options.
If you’re testing your story on the computer, the web previewer doesn’t remember gains/choices from previous chapters. What you can do is click on Navigation then click on “Enable Picker”. This tool comes in handy so you can test out if/elif/else statements. So any time you play through your script and it gets to the if/elif/ese, a “choice” will pop up with the option to play through whichever branch you want to test/play through.
But of course it all comes down to if you wrote the if/elif/else correctly. You may not get any errors when you click on save, but if the if/elif/else is not formatted correctly then it will not work when you test your story.