Using milliseconds for a unique ID

Hello, I am following Creating Unique Serial Numbers in Forms — KoboToolbox documentation to create a unique ID, but it seems that ‘now()’ doesn’t show up. See form and preview below. Does anyone know how to fix this? Many thanks in advance!

Welcome to the community, @danstori! Maybe you could follow this post discussed previously:

Thanks very much for the welcome and the useful help @Kal_Lam ! Very helpful. In the end I went forward with the uuid() function.