I would like my agent to search a Google sheet as soon as the call comes in via a web hook with Zapier. and a get_user_details function. I don't know how to write the function JSON and I don't know if I put the right code into Zapier to extract the proper variables. I really confused as to what to put where.

Hello! I'm new here! I'm trying to understand retell AI conversational prompt! 😅. Got stuck at the beginning where I would like the voice agent to search a google sheet for user name and if found use the name to greet the caller. I have the webhook set up in Zapier still confusing. the functions/json is giving me trouble! Happy to be here 😁