Custom Properties

I am building a Sign-up Form and I'm trying to add a Radio Button question to collect customer preferences.

The Goal: I want the answer to be saved as a new Custom Property on the profile.

The Problem: In the form editor, under "Profile Property", I am struggling to create a new property.

1. When I type a new name, it doesn't seem to register or create the property key.

2. I am also confused about the "Value" field vs the "Label".

Currently, when I test the form, the data is not appearing under the "Custom Properties" section of the profile.

Question: How do I correctly set up a Radio Button block so that it automatically creates a new Custom Property with the specific Value I entered?

Screenshots attached of my current settings.

Thanks.