From what I've seen, the interactive checkboxes used in the "Getting Started" activity requires their Data Interactive Plugin API and coding knowledge. Clicking on the little "i" in the bottom right corner of the box with the interactive checks in the "Getting Started" document, it says,
"This onboarding plugin for CODAP was created to help new CODAP users get started using CODAP. It lives in CODAP as an iFrame. Certain user actions cause CODAP to notify the plugin. The plugin responds by providing feedback to the user.
The open source code is at
CODAP's data interactive GitHub repository.
This plugin makes use of the CODAP data interactive plugin API whose documentation is at
CODAP Data Interactive API."
So, I don't think there is an easy way to make the interactive checkboxes.