The best way to see how activities are made is to use the "copy and edit" feature of activity builder.
1. Make sure you are signed in
2. Near the activity title, there is an icon that looks like three vertical dots. Click it, and select "copy and edit"
3. Find the screen you're interested, and click "Edit Graph" to see the expressions (including secret folders) that were used to make it.
I should note that this group is intended for discussion of the Desmos API (
https://www.desmos.com/api). General support requests about how to use tools or activities should be directed to
sup...@desmos.com.