Click on + icon to add a card to the chat.
2. Select "Hidden variable assignment" card from the list.
3. Select the hidden variable you want to add to the chat.
4. Click "ADD TO CHAT"
5. Hidden variable assignment card is added to the chat. Click "EDIT SCRIPT" to add the script to compute hidden variable.
6. Click "SAVE AND VALIDATE" to save the script.
7. Click "CLOSE" to close the edit script drawer.
