Hi @chandan988, as suggested in Multiple json received via webhook - #3 by MutedJam, transforming a single array into separate items sounds like a case for the Item Lists node. If you need help with this, it would be great if you could post an example of the data you already have.
This transformation would btw also be required once the registrants resource is available in the Zoom node as it returns the registrants in an array field named registrants, similar to the data structure used by the Zoom API:
On that note, I have run some more tests using the uncommented existing code. In addition to fetching registrants I could create them, but updating them still fails, so this needs some more work I am afraid.